Methods for incising tissue

ABSTRACT

An elongate electrode is configured to flex and generate plasma to incise tissue. An electrical energy source operatively coupled to the electrode is configured to provide electrical energy to the electrode to generate the plasma. A tensioning element is operatively coupled to the elongate electrode. The tensioning element can be configured to provide tension to the elongate electrode to allow the elongate electrode to flex in response to the elongate electrode engaging the tissue and generating the plasma. The tensioning element operatively coupled to the flexible elongate electrode may allow for the use of a small diameter electrode, such as a 5 μm to 20 μm diameter electrode, which can allow narrow incisions to be formed with decreased tissue damage. In some embodiments, the tensioning of the electrode allows the electrode to more accurately incise tissue by decreasing variations in the position of the electrode along the incision path.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.17/250,965, filed Apr. 2, 2021, which is a 371 national phase ofPCT/US2020/070757, filed Nov. 6, 2020, published as WO 2021/092628 A1 onMay 14, 2021, and claims the benefit under 35 U.S.C. § 119(e) of U.S.Provisional Patent Application No. 62/931,226, filed Nov. 6, 2019, andU.S. Provisional Patent Application No. 62/966,925, filed Jan. 28, 2020,the entire disclosures of which are incorporated herein by reference.

The subject matter of the present application is related to U.S.Provisional Patent Application No. 62/909,092, filed Oct. 1, 2019, theentire disclosure of which is incorporated herein by reference.

BACKGROUND

Tissue ablation and incisions can be used to in many ways to performprocedures such as surgical procedures. For example, lasers can be usedto correct refractive error such as myopia, to remove cataracts, and totreat glaucoma and retinal disease. Tissue ablation and incisions canalso be used orthopedics and cardiology to perform surgical procedures,for example.

Work in relation to the present disclosure suggests that the efficacyand availability of surgical procedures may be related to limitations ofthe devices used to incise and ablate tissue in at least some instances.For example, lasers such as femtosecond lasers can be complex, and thetreatments may take longer than would be ideal. Also, the tissue removalprofile along a laser induced incision may not be as smooth as would beideal in at least some instances. Also, with laser treatments tissueartifacts and debris such as a plume associated with the laserirradiation can affect the accuracy and effectiveness of ablations andincisions.

Although mechanical cutting with blades such as microkeratome blades canbe used for some surgical procedures, work in relation to the presentdisclosure suggests that mechanical cutting with blades can be lessaccurate and may produce rougher surfaces than would be ideal in atleast some instances. Although mechanical keratomes have been used tocreate corneal flaps for surgical procedures such as LASIK, work inrelation to the present disclosure suggests that mechanical keratomescan take somewhat longer than would be ideal, and the resulting flapsmay be some irregular and rougher than would be ideal in at least someinstances. Although a scalpel or diamond knife may be used to manuallyresect two separate flaps within tissue, such as scleral and/or cornealtissue in traditional canaloplasty, this can be technique dependent andsomewhat difficult for at least some practitioners, which may be relatedpostoperative complications. It would be helpful to reduce techniquedependency and postoperative complications.

Although, femtosecond lasers have been used to create corneal flaps andpockets, work in relation to the present disclosure suggests that thetime to form the flaps and pockets may take longer than would be idealin at least some instances. The Small Incision Lenticule Extraction(SMILE) procedure is a more recent approach to reshaping the cornea thatutilizes a femtosecond laser system to ablate tissue along theboundaries of a 3-dimensional lenticule within the corneal stroma, whichmay be removed through a corneal opening. However, work in relation tothe present disclosure suggests that the 3-dimensional lenticule formedand removed with this procedure may be less than ideally shaped in atleast some instances. Also, the amount of time to ablate tissue thatdefines the lenticule and opening can be somewhat longer than would beideal.

Although electrodes have been proposed to treat tissue, the priorapproaches can result in more tissue damage and less precise incisionsthan would be ideal. Although electrodes that generate plasma have beensuggested, these prior approaches may not be well suited for cuttinglarge volumes of tissue and the accuracy can be less than ideal in atleast some instances.

In light of the above, there is a need for improved approaches totreating tissue with incisions that ameliorate at least some of theaforementioned limitations. Ideally, such approaches would decreasecomplexity and treatment times and provide more accurate incisions withimproved outcomes.

SUMMARY

Embodiments of the present disclosure provide improved methods andsystems for incising tissue. In some embodiments, an elongate electrodeis configured to flex and generate plasma to incise tissue. Anelectrical energy source can be operatively coupled to the electrode andconfigured to provide electrical energy to the electrode to generate theplasma. In some embodiments, a tensioning element is operatively coupledto the elongate electrode. The tensioning element can be configured toprovide tension to the elongate electrode to allow the elongateelectrode to flex in response to the elongate electrode engaging thetissue and generating the plasma. In some embodiments, the tensioningelement operatively coupled to the flexible elongate electrode allowsthe use of a small diameter electrode, such as a 5 um to 20 um diameterelectrode, which can allow narrow incisions to be formed with decreasedtissue damage. In some embodiments, the tensioning of the electrodeallows the electrode to more accurately incise tissue by decreasingvariations in the position of the electrode along the incision path.

In some embodiments, the elongate electrode is operatively coupled toone or more components to allow tissue resection along a path. Theelongate electrode can be coupled to a support structure that moves withthe electrode to provide an incision along a path. The support structurecan be configured to support one or more arms, such as a plurality ofarms, which arms support the electrode suspended between the arms. Thesupport structure, one or more arms, and the elongate electrode maycomprise components of an electrode assembly. The electrode assembly canbe operatively coupled to a translation element to provide translationalmovement to the electrode in order to incise tissue. In someembodiments, a contact plate is configured to engage tissue to shape thetissue prior to incision with the elongate electrode, which can provideimproved accuracy of the incision and the shape of tissue to be removed.

In some embodiments, a gap extends between the support structure and theelectrode suspended between the arms, which can provide bidirectionaltissue incisions and decrease treatment times. In some embodiments, thegap is sized to receive tissue and to incise tissue that extends intothe gap when the support structure and electrode are drawn proximally.In some embodiments, the support structure and electrode are advanced tointo the tissue to incise the tissue with a first incision on a firstpass with a first configuration of one or more contact plates, and thesupport structure and electrode drawn proximally to incise tissue with asecond configuration of the one or more contact plates. In someembodiments, the second configuration is different from the firstconfiguration, and tissue incised with the first pass extends into thegap and is incised with the second pass so as to provide a resectedvolume of tissue for subsequent removal. In some embodiments, theresected volume of tissue comprises a thickness profile corresponding toa difference between a first profile of the first configuration and asecond profile of the second configuration of the one or more contactplates. In some embodiments, a lenticule corresponding to a refractivecorrection of an eye is incised with the first pass and the second pass,and the lenticule can be subsequently removed to provide the refractivecorrection.

In some embodiments, an elongate electrode is configured to incisetissue such as corneal tissue. An electrical energy source isoperatively coupled to the elongate electrode and configured to provideelectrical energy to the electrode. A contact plate is configured toengage a portion of the tissue such as the cornea to shape the tissueprior to incising the cornea with the electrode. A support structure canbe operatively coupled to the elongate electrode and the plate, thesupport configured to move the electrode relative to the plate andincise the corneal tissue with the electrode.

INCORPORATION BY REFERENCE

All patents, applications, and publications referred to and identifiedherein are hereby incorporated by reference in their entirety and shallbe considered fully incorporated by reference even though referred toelsewhere in the application.

BRIEF DESCRIPTION OF THE DRAWINGS

A better understanding of the features, advantages and principles of thepresent disclosure will be obtained by reference to the followingdetailed description that sets forth illustrative embodiments and theaccompanying drawings listed below.

FIG. 1A is directed at a schematic image of an eye shown in crosssection to show anatomical locations therein, in accordance withembodiments of the present disclosure.

FIG. 1B is directed at a plot displaying a relationship between themeasured threshold discharge voltage and pulse duration for negative andpositive voltages for a single long, thin electrode, in accordance withembodiments of the present disclosure.

FIGS. 2A through 2F depict examples of different conditions encounteredwith varying electrode-to-tissue spacing and/or the electrode voltage,in accordance with embodiments of the present disclosure.

FIG. 3 is directed at a plot displaying a relationship between themeasured negative threshold voltage and electrode diameter for a fixedpulse of varying duration, in accordance with embodiments of the presentdisclosure.

FIGS. 4 & 5 are directed at an electrode subsystem of a system to incisea target tissue structure, in accordance with embodiments of the presentdisclosure.

FIG. 6 is directed at a system to incise target tissue structure, inaccordance with embodiments of the present disclosure.

FIG. 7 depicts a flow chart describing steps to practice a method, inaccordance with embodiments of the present disclosure.

FIGS. 8A through 8D are directed at a system to incise a target tissuestructure, in accordance with embodiments of the present disclosure.

FIG. 9 depicts a flow chart describing steps of a method, in accordancewith embodiments of the present disclosure.

FIGS. 10A through 10F are directed at a system to incise a target tissuestructure, in accordance with embodiments of the present disclosure.

FIGS. 11A and 11B are directed at a piecewise adjustable contactelement, in accordance with embodiments of the present disclosure.

FIGS. 12A and 12B are directed at a disc-shaped lenticule, in accordancewith embodiments of the present disclosure.

FIGS. 13 through 15 are directed at different lenticule configurations,in accordance with embodiments of the present disclosure.

FIGS. 16A and 16B are directed at histological images of porcine corneascontaining incisions made, in accordance with embodiments of the presentdisclosure.

FIG. 17 is directed at a plot displaying an exemplary electrode voltageversus time, in accordance with embodiments of the present disclosure.

FIG. 18 is directed at a high-speed video image of a porcine corneabeing incised, in accordance with embodiments of the present disclosure.

FIGS. 19A-19D depict aspects of a tissue “flap” and aspects of a tissue“pocket”, in accordance with embodiments of the present disclosure.

FIG. 20 depicts aspects of a system that is configured to create atissue flap or a tissue pocket, in accordance with embodiments of thepresent disclosure.

FIG. 21 depicts aspects of a system, in accordance with embodiments ofthe present disclosure.

FIGS. 22A-22C are directed at details of an electrode, in accordancewith embodiments of the present disclosure.

FIG. 23 is directed at a system, in accordance with embodiments of thepresent disclosure.

DETAILED DESCRIPTION

The following detailed description and provides a better understandingof the features and advantages of the inventions described in thepresent disclosure in accordance with the embodiments disclosed herein.Although the detailed description includes many specific embodiments,these are provided by way of example only and should not be construed aslimiting the scope of the inventions disclosed herein.

The presently disclosed systems and methods are well suited forincorporation into prior devices and surgical procedures, such asmicrokeratomes, incising tissue to form one or more of flaps, pockets,or lenticles for removal from tissue, e.g. SMILE. The presentlydisclosed methods and systems are well suited for combination with lensremoval and prosthesis, such as removal of the lens nucleus and cortexfor placement of an intraocular lens. By way of non-limiting example, aplasma-induced incision may be created in the capsule to produce acapsulorrhexis. Incisions may be created in the to produce lensfragments or to simplify lens fragmentation and/or lens removal. Theincisions may be formed in the retina to produce a pocket or flap. Insome embodiments an incision is formed in the TM to improve drainageand/or to lower intraocular pressure (“IOP”) for the treatment ofglaucoma, or in the iris to produce an iridotomy for example.

Although reference is made to incisions in tissues of the eye, thepresently disclosed systems and methods are well suited for formingincisions in non-ophthalmic surgeries such as orthopedic surgery,cardiovascular surgery, neurosurgery, robotic surgery, pulmonarysurgery, urologic surgery, and soft tissue surgery. Although referenceis made to cutting ocular tissue, the presently disclosed methods andsystems are well suited to forming incisions in one or more ofcollagenous tissue, cartilage, stromal tissue, neural tissue, vasculartissue, muscle and soft tissue.

By way of non-limiting example, FIG. 1A illustrates various anatomicallocations in eye that may be suitable for practicing the presentdisclosure. The eye includes a cornea, a sclero-corneal limbus, asclera, a lens capsule, a lens, a retina, an iris, and a trabecularmeshwork TM. Although not shown for purposes of clarity, a Schlemm'scanal may be located adjacent to TM. The presently disclosed systems canbe used to treat any of these locations. In some embodiments, the corneais shaped to provide refractive treatment of the eye. In someembodiments, the sclera is incised, for example to provide a filteringbleb to treat glaucoma. In some embodiments, at least a portion of thecapsule is incised, for example so as to access the cortex and nucleusof the lens. In some embodiments, at least a portion of the lens isincised and resected. In some embodiments the retina is treated, forexample with the electrode. In some embodiments, the IRIS is incisedwith the electrode. In some embodiments, tissues associated with TM andSchlemm's canal are incised, for example with reference to glaucomasurgery.

In some embodiments, the application of a sufficient voltage, includinga periodic or pulsatile voltage, to an electrode in or around abiological tissue (i.e., a “target tissue structure”) may result in theformation of a vapor in proximity to said electrode that derives fromthe initial current and/or the electric field established by heating atleast a component of said tissue (e.g., water within a tissue) to abouta vaporization temperature (or a “critical temperature”, e.g. —100° C.for pure water at standard pressure). The contents of such a vaporcavity may then be ionized by said electrode voltage to disrupt (orequivalently, “ablate”) at least a portion of said target tissuestructure, especially if the pulse duration of a pulsatile voltagewaveform is sufficiently short when compared to the thermal relaxationtime of the target tissue structure and thermal confinement is achievedand the amount remaining damaged tissue created thereby may beminimized. The creation of said vapor may be due to a phase changeprocess and thus a concomitant temperature increase may cease once thevaporization temperature is reached via a latent heat process. Thevolume of said vapor cavity (or equivalently, “bubble”) may increase asthe amount of vapor is increased and may further scale directly with theelectrode voltage and/or the current supplied by said electrode to thetissue as larger volumes of tissue are heated. Likewise, and/or pressurewithin said bubble may increase as the amount of vapor is increased andmay further scale directly with the electrode voltage and/or the currentsupplied by said electrode to the tissue as larger volumes of tissue areheated. Subsequently, a plasma may be formed at least partially withinsaid vapor cavity by ionizing the vapor should said electrode beoperated with a voltage great enough such that the resultant electricfield strength within the vapor cavity exceeds a discharge threshold tocreate a plasma-induced ablation, a combination of which when createdalong an electrode may create a plasm-induced incision. By way ofnon-limiting example, said discharge threshold may be selected from thegroup consisting of: an ionization threshold, an electrical breakdownthreshold, a dielectric breakdown threshold, a glow discharge threshold,an ablation threshold, a disruption threshold, and combinations thereof.If the electrode voltage is great enough, the resultant electric fieldstrength may allow for secondary discharge and produce an arc. Avoidingsuch arc discharge may be advantageous, as will be described elsewhereherein. Said plasma may allow electrical current to again flow throughthe electrode, the vapor, and the tissue, and my thus cause a furthertemperature increase. The bulk electrode temperature may be directlyproportional to the amount of current flowing said electrode and/or tosurface bombardment of ions and charged particles, chemical reactions,and radiation; which themselves may be functions of the amount of plasmagenerated. Energy may be efficiently delivered to a target tissuestructure to achieve thermal confinement within at least a portion of atarget tissue structure that is nearby the electrode and/or the vaporcavity to create and/or sustain said vapor cavity. Thermal confinementmay be achieved if said energy is deposited in a target at an energydeposition rate that is greater than an energy dissipation rate; such asmay be when a current only flows through a tissue nominally within atime that is less than or equal to about a thermal time constant of saidtissue, such as may be achieved using a periodic or pulsatile voltage.Said thermal time constant may be a thermal relaxation time, as definedby the size or shape or geometry of the electrode, the size or shape orgeometry of the vapor cavity, and combinations thereof. A time constantmay alternately be defined as a mechanical response time, such as adisplacement relaxation due to a transient deformation of tissueadjacent to a collapsing vapor cavity. For a semi-infinite slab ofmaterial, said thermal relaxation time r may be approximated by

${\tau \approx \frac{d^{2}}{4\alpha}},$

where d is the distance into the tissue, and α is the thermaldiffusivity of the tissue. For sclera and cornea α is ˜0.14 mm2·s⁻¹. Forexample, such a thermal relaxation time for a d=˜2 μm damage extent isτ=˜28 μs. Damage is defined herein as at least partially denaturedtissue or at least partially denatured tissue components caused by themechanism for creating the incision, such as plasma, heating, etc. Suchmechanical response times may be dictated by the material'scompressibility and density, which in turn may be related to the tissuehydration. For most species including humans, water may contribute ˜76%of the weight of the corneal stroma.

In some embodiments, for example related to soft tissues, the followingrelations may be used to approximate the mechanical properties of saidtissue;

${M = {K + {\frac{4}{3}G}}},$

where K and G are the bulk and shear moduli, respectively, and

${G \ll K},{{M \approx K} = \frac{1}{\beta}},$

where β the tissue compressibility and the mean elastic modulus ofcorneal tissue may range between ˜1 and ˜3 MPa. Thus, a sufficientlyintense and rapid increase in the temperature of a material (i.e. atissue, or the constituents or components of a tissue) may cause anamount of said material to be vaporized. Said vaporization may be anexplosive vaporization that disrupts the tissue; i.e. causes tissue“disruption,” also known as tissue “breakdown,” and tissue “rupture,”and tissue “ablation.” The extent of a vapor cavity may intrinsicallymediate the plasma discharge process when operated as described in an atleast partially compressive material, such as tissue, due to transientmechanical deformation and displacement of said material as an electricfield strength may decrease as the square of the distance from anelectrode (e.g. ∝ r²) and a discharge may cease when the bubble grows tothe extent that the distance from the electrode surface to the bubblesurface is too large to continue to support said discharge throughout avapor cavity with the operating voltage because the electric fieldstrength may be commensurately diminished. Maintaining a glow-type ofdischarge or disallowing an arc-type of discharge may be beneficial toproducing precise incisions with minimal collateral damage. Flashes oflight may accompany the plasma. The rate of said flashes of light may bedependent upon a velocity. The intensity of said flashes of light may bedependent upon an energy per pulse, or the power to the electrode.

In some embodiments, the required voltage and associated energydeposition may be reduced by decreasing the width of the electrode, asshown in FIG. 1B, which contains plot 600; a relationship between thenegative voltage threshold for tissue vaporization versus the diameterof a long cylindrical electrode for ˜50 μs pulses using electrodelengths of ˜1 mm, ˜2 mm, ˜5 mm, and ˜10 mm corresponding to curves 602,604, 606, and 608, respectively. Such electrodes may be deemed “elongateelectrodes” due to the aspect ratio between a width and a length of saidelectrode. That is, an elongate electrode comprises a cross-sectionaldistance that is significantly smaller than its incisional length. Thisvoltage may be made to be as low as possible and cutting with thisvoltage may be possible when the voltage exceeds the breakdown thresholdwithout allowing for significant thermionic emission, where significantrefers to an amount that noticeably contributes to tissue thermal damagebeyond what would otherwise be present. An electric field around anelectrode may scale with distance r is as follows,

${E = \frac{E_{e}r_{e}}{r}},$

where E_(e) is the electric field at the surface of the electrode andr_(e) is the radius of the electrode. Thus, the difference in electricalpotential on the surface of the electrode to that at distance R from anominally cylindrical elongate electrode may be

${\Delta{U(R)}} = {{\int_{R}^{r_{e}}{{E(r)}{dr}}} = {E_{e}r_{e}{{\ln\left( \frac{R}{r_{e}} \right)}.}}}$

Thus, it may be that the electric field becomes nominally spherical atdistances larger than the length of the electrode, L, and we may assumethat at distances comparable to L the potential drops to zero; yielding

$\frac{U_{e}}{\ln\left( \frac{L}{r_{e}} \right)}.$

The power density of the Joule heat generated by a current density j ina conductive material with resistivity γ may be

$w = {{j^{2}\gamma} = {\frac{U_{e}^{2}}{r_{e}^{2}{{\gamma ln}\left( \frac{L}{r_{e}} \right)}^{2}}.}}$

The minimal energy density A required for vaporizing the surface layerof water within a tissue may be A=wτ=ρC ΔT, where ΔT is the temperaturerise of a liquid layer during a pulse of duration τ, ρ=˜1 g/cm³ isdensity of water, and C=˜4.2 J·g⁻¹·K⁻¹is its heat capacity. Thus, thevoltage U required for vaporization may be

$U = {r_{e}{\sqrt{\frac{\rho C\Delta T\gamma}{\tau}{\ln\left( \frac{L}{r_{e}} \right)}}.}}$

This voltage and associated energy deposition may be reduced bydecreasing the thickness of the electrode, i.e. the radius of theaforementioned wire. Pulse durations r may be kept shorter than athermal relaxation time τ_(r) of a target tissue structure for a givenelectrode geometry. For example, the 1/e relaxation time for a longcylinder may be

${\tau_{r} \approx \frac{d^{2}}{9.32\alpha}},$

where

$\alpha \equiv \frac{k}{\rho C}$

is the thermal diffusivity of the material, and k being the thermalconductivity, which may yield a τ_(r) of ˜65 μs fora ˜20 μm diameterpure tungsten wire electrode, or ˜1/5^(th) that of an equivalentcylinder of water or tissue, as α_(tungsten)=0.66 mm²·s⁻¹ andα_(tissue)=˜0.14 mm²·s⁻¹. It may be noted from these curves that for awire electrode of length of ˜10 mm and diameter of less than ˜30 μmutilizing a negative voltage of ˜−200V may be appropriate for incising atarget tissue structure while maintaining a margin of ˜200V between thepositive going breakdown threshold, as will be described elsewhereherein.

In some embodiments, discharge may start from vaporization of tissuearound electrode and may continue when voltage is high enough to bridgethe ionized gas-filled vapor gap between the electrode and the tissue.If the voltage is not enough to maintain such a vapor cavity along theentire length of electrode, liquid may contact the electrode, and allowan electrical current through that interface. The depth of heating maybe proportional to the length of the liquid-electrode interface. Thus,the extent of the damage zone may increase with decreasing voltage foran otherwise fixed system. Greater voltage may correct for this, but ifthe voltage exceeds both negative and positive plasma thresholds, theelectrode may become too hot and the plasma discharge may beself-sustained, as will be described elsewhere with respect to FIG. 3 .Thermionic emission may be avoided to limit collateral damage to tissue.Turbulence may break the vapor cavity and both electrode and tissue maybe damaged. An electrode may be so thin that a small voltage can supportthe vapor cavity and said voltage may be slightly above plasmathreshold. A small thickness of vapor cavity may be maintained around atleast a portion of the electrode at voltages lower than any plasmathreshold. Translating the electrode may allow for contact of a smallregion of tissue and may be conceptualized as a single point of contact,or point-like contact. Such point-like contact may cause suddenvaporization, ignite a plasma discharge in the commensurately confinedvolume and disrupt tissue thereby. After a section of tissue isdisrupted in this manner, a different section of the tissue may bealready touching the advancing electrode elsewhere, leading to a nextvaporization, discharge, and subsequent disruption in this region. Theamalgamation of such disruptions may be considered an incision. The heatdistribution around a point-like discharge may be nominally spherical.The extent of heat deposition may be short and may scale as r⁴ where ris radius of discharge and the tissue damage zone may now depend more onthe radius of electric discharge and less on length of electrode. If theradius of the point-like discharges is in the ˜10 μm range, a sequenceof such discharges may cut the tissue in a “punctuated” or “staccato”fashion by repeatedly breaking down different regions (i.e., atdiscontiguous locations or, equivalently, non-overlapping regions) oftissue along the electrode length and may leave a damage zone of onlyabout a few μm in thickness. A constant arc may be avoided, and plasmamade to remain in the glow regime by repeatedly breaking down regions oftissue and thereby modulating the electrode voltage to minimize damagefrom thermionic and resultant thermal effects. The different regions oftissue within a target tissue structure that may be repeatedly brokendown may be adjacent to each other but need not.

FIG. 2A illustrates electrode assembly 4 approaching tissue 2 alongdirection 12, where gap 622 exists between electrode assembly 4 and theclosest region of tissue to the elongate electrode, tissue region 620.In this exemplary embodiment, both ends of electrode assembly 4 areconnected in parallel to driver 18 via connections 20 and the returnpath to driver 18 is via connection 22 from return electrode 24. Driver18 may be considered to be an electrical energy source that provideselectrical energy to the electrode in order to produce plasma within atarget tissue structure.

FIG. 2B illustrates the initial instantaneous connection of tissue 2 toelectrode assembly 4 at contact region 620, wherein gap 622 hasdecreased to ˜0.

FIG. 2C illustrates a condition wherein the magnitude of the voltage onelectrode assembly 4 is above at least a negative voltage plasmathreshold value in region 620 (not shown) which may cause vaporizationof at least a component of tissue 2 within tissue region 626 to create avapor cavity 635 and may allow current 624 to flow to return electrode24 and may create damage zone 628. Such damage zone 628 in turn may belimited in extent to a volume of tissue directly adjacent to tissueregion 620 and either of such tissue regions 625 & 627 may be the nextportion of tissue 2 to be instigate vaporization in the same manner asregion 620 did previously to create a staccato processes, as describedelsewhere herein. Discharge may start from the vaporization of tissuearound electrode and may continue while voltage is high enough to bridgethe vapor gap between the electrode and the tissue and ionize the vaporin the gap. If a portion of such an electrode has no contact with thetissue, for example, as may be the case when a vapor bubble has beenformed about that region of the electrode, the electrode temperature mayrise and increase in resistivity. For example, as may happen when aportion of a wire consumes more current than another portion of the wirewhen connected in series to a power source that is in“power-limiting-mode”, as the average power may stay constant, butlocalized overheating in regions of increased resistivity may cause theportion of the wire to evaporate and break. However, this may bereduced, e.g. avoided, if an electrode is placed at a common voltage,such as may occur if both ends of a wire are connected to the samelocation in a circuit (or “node”). In this exemplary configuration, whenone portion of the electrode may become more resistive due tooverheating and the current may go through another portion of theelectrode, wherein the current through the heated region may decreaseand preserve the wire from failing as described earlier with respect tothe serial connection configuration. The velocity of a moving electrodemay be chosen to satisfy the condition of constant tension below therupture tension of the wire. Too little tension may reduce saidvelocity. If an electrode is not in contact with tissue, there may be noheat transfer from the electrode to the tissue and the electrodetemperature may increase. An arc current may then increase due to theelectrode temperature increase and may instigate a positive feedbackloop, which may in turn cause an overheating of tissue and/or theelectrode when the electrode is under slack and/or low tensionconditions that reduce the likelihood of a small region tissuecontacting the electrode to produce the aforementioned staccatodischarge. Since the plasma threshold is polarity dependent, thedischarge may work as a rectifier and a rectified current may be used asfeedback for cutting at about a minimum negative voltage threshold forplasma discharge, including by way of non-limiting example operation inthe glow discharge regime. In this configuration the damage zone may nowdepend on the radius of the electric discharge instead of the electrodelength. A punctuated sequence of discharges whose extents are in the ˜10μm range may result in a damage zone thickness of between ˜1 μm and ˜3μm. The duty cycle of the power supply (e.g. driver 18, or “electricalenergy source”) in this configuration may be kept at ˜100% due to thepunctuated discharge process.

FIG. 2D illustrates a condition wherein the voltage on electrodeassembly 4 is below a plasma threshold value and may fail to maintain amaintain a vapor cavity 635 such as region 626 of the previous figureand may cause contact region 620 to expanded along electrode assembly 4to produce extended contact region 630, which is larger than contactregion 620, and may allow for more current 624 to flow from electrodeassembly 4 through tissue 2 to return electrode 24, producing a largerdamage zone 628 than that of FIG. 2C, which may extend to portion oftissue 2 behind direction 12 via thermal conduction. If the electrodevoltage cannot maintain a vapor cavity 635 along the electrode, tissueand/or liquid may contact the electrode and allow a large currentthrough the interface. The extent of the damage may be proportional tothe length of the electrode-tissue interface; i.e. extended region 630.Thus, a damage zone extent may increase with a decrease of voltage.Similarly, large damage zone may occur if no voltage is supplied to theelectrode prior to its contacting tissue, as a relatively large portionof said electrode may simultaneously contact tissue before a dischargeprocess initiates. To avoid such damage, a suprathreshold voltage may beapplied to the electrode before it contacts tissue and an incision beproduced as described with respect to FIG. 2C. Another way to protecttissue from overheating may be by using nonconductive liquids likeElectro Lube Surgical, or viscoelastic substances (e.g. Healon). Suchnonconductive liquids may serve as both a cooling agent and protectionagainst current-related tissue damage such as electroporation. Forexample, a nonconductive liquid may be injected into the cutting regionto protect tissue nearby the target tissue which may be in the currentreturn path. Nonconductive liquid may also be cooled before use.

FIG. 2E illustrates a condition wherein the magnitude of the voltage onelectrode assembly 4 may be greater than both a negative plasmathreshold value and a positive plasma threshold value and contact region620 has expanded along electrode assembly 4 to produce a vaporizationregion 626 that may be greater than that of the vaporization region 626in FIG. 2C. Likewise, more current 624 may flow from electrode assembly4 through tissue 2 to return electrode 24 in this configuration thanthat of FIG. 2C, producing a larger damage zone 628 than that of FIG.2C. An electrode voltage exceeding both negative and positive plasmathresholds may cause the electrode to become hot enough to provideself-sustained thermionic emission. Turbulence may interrupt vaporcavity 635 and may damage the electrode and/or the tissue.

An elongate electrode may comprise a nominally circular cross sectional(or “round”) wire and decreasing the electrode width may be equivalentto reducing the diameter (or, equivalently, its “cross-sectionaldistance”) of said wire. This voltage may be kept as low as possiblewhile still rupturing tissue to avoid overheating of a target tissue.The electric field from a nominally cylindrical electrode may tendtoward zero at distances on the order of the electrode length, which mayin turn cause unnecessarily extended damage zones in tissue when usingsuch an electrode with an aspect ratio >>1 (e.g., when the electrodecomprises a long, thin wire). A staccato process of tissue breakdown asdescribed herein may provide for a reduced damage zone due to theintrinsic interruption of current flow through tissue that may accompanysaid approach, as in the absence of tissue disruption electrical currentmay nominally only substantially flow through tissue when the tissue iscontact with the electrode.

Although usually circular in cross-section, wire can be made in square,hexagonal, flattened rectangular, or other cross-sections. Thus, anelectrode may be alternately configured using a nominally non-circularcross-sectional conductor, such as that of a rectangular cross-section.Such nominally non-circular cross-sectional wire may be available fromEagle Alloys (Talbott, Tenn.). Rectangular cross-sectional electrodesmay be created by stamping a foil sheet, such as those that also may beavailable from Eagle Alloys (Talbott, Tenn.). A non-circularcross-section electrode may be further configured such that its thinnestdimension is nominally parallel to the translation direction to providefor electrode deformability along the translation direction andincreased stiffness in the orthogonal direction. A conducting wire orthread with a high melting point, forming part of an electric circuitmay be referred to as a filament as will be appreciated by one ofordinary skill in the art.

FIG. 2F illustrates a condition wherein electrode assembly 4 may becomprised of electrode regions 650, 652, and 654, which need notrepresent the entire incisional length. The electrode as shown hasdeformed during an incision and electrode regions 652 and 654 aredisplaced in the direction of motion 12 while electrode region 650 isnot, which may occur when at least one of the electrode regions 650through 654 is flexible. By way of non-limiting example, configuringelectrode assembly 4 to be flexible, such as by using a thin wire, forat least a single region of an electrode regions 650 through 654 mayprovide said deformability. In the exemplary embodiment, a new closestregion of tissue to the electrode, most proximal tissue region 620 isnow approached by electrode region 652 and most proximal tissue region620 is what was tissue region 625 of FIG. 2C and may be the next portionof tissue 2 to instigate vaporization in the same manner as region 620did previously to create a piecewise incision. The shape of tissue 2 maybe altered by the ablation of at least a single tissue region and thuscause a portion of tissue 2 to instigate vaporization in the same manneras region 620 did previously to create a piecewise incision.

FIG. 3 shows plot 610; measured relationships between the polaritydependent voltage thresholds for vaporization versus pulse duration fora negative voltage discharge (curve 614) and a positive voltagedischarge (curve 612) using a pulsatile voltage delivered with a ˜8 mmlong ˜Ø50 μm tungsten wire electrode submerged in a bath of aphysiologically balanced salt solution and observing such dischargeusing a camera. The lower threshold voltage for the negative dischargeregime may lend itself to creating an incision with less damage thanthat of the positive discharge regime due to the concomitant lowercurrents. Thus, driver 18 may be configured to utilize a negativevoltage bias. p A pulsatile voltage waveform may be used to create aplasma as described. In water, for example, a vapor cavity may expand ata mean velocity of ˜0.5 m·s⁻¹, as averaged over a bubble lifetime of˜500 μs, away from a ˜Ø20 μm thick electrode operating with a nominallysinusoidal waveform having a peak voltage of ˜300V, causing discharge tocease due to a collapse of the vapor bubble (and possible subsequentcavitation), which may transfer momentum between the material and theelectrode. In this configuration, the time required to reignite a plasmamay be on the order of milliseconds, which may be long in comparison tothe pulse period of the energizing waveform in the ˜MHz regime andrequire considerably greater voltage to sustain discharge. However, ifthe distance between the tissue and the electrode surface is reduced,such as by moving the electrode, breakdown may be reinitiated sooner.The velocity of the resultant incision produced by the plasma may bereferred to herein as the “tissue velocity.” The frequency of apulsatile electrode voltage may be configured in the ˜MHz range andallow for a plurality of cycles during a tissue breakdown and/or abubble lifetime. By way of non-limiting example, the nominal type ofsaid waveform may be selected from the group consisting of: a sinusoidalwaveform, a square-wave waveform, a triangle-wave waveform, a rampwaveform, a periodic waveform, a non-periodic waveform, and combinationsthereof. The amount of time it takes for the electrode to move intotissue contact and the amount of time it takes for vaporization may belonger than the amount of time it takes to complete a discharge process.An electrode may be cooling when not disrupting tissue and the time anelectrode is in contact with tissue and not disrupting tissue may causetissue damage due to thermal diffusion from the electrode into thetissue, which may in turn require more energy to overcome a reducedelectrode temperature. Thus, a lower incisional duty cycle may engenderconcomitantly greater thermal damage to tissue than a higher incisionalduty cycle.

In some embodiments, the failure to achieve thermal confinement mayresult in collateral tissue damage. Such as may be the case for a rigidelectrode, as the velocity at all locations along the electrode isconstant, but the velocity of the tissue along the electrode may not beconstant, i.e. there may be a distribution of tissue velocities in bothtime and space along the cutting edge of an electrode. A rigid electrodecan only move as fast as the slowest cutting velocity it achieves. Thatis, a rigid electrode may need to incise a complete path along itscutting edge in order to advance and incise further, thus causingregions of tissue to compact onto the electrode prior to being incisedand limit the instantaneous cutting velocity by allowing only an averagecutting velocity. Hot spots along the cutting edge of a rigid electrodemay provide for punctate vaporization, but those same locations may thenlinger in tissue awaiting similar breakdown at other locations, evenwith a rigid elongate electrode. The time spent lingering may be longerthan a thermal or a mechanical response time of a tissue and result incollateral damage due to heat dissipation into tissue, especially in thepresence of excessive liquid. A more efficient use of energy may be thedesiccation of a next region of tissue to be incised. Actuating a rigidelectrode at too fast a translation rate may not allow for a completeincision and cause “traction.” Collateral damage may be thus reduced ifthe actuated velocity of an electrode nominally accommodates thedischarge velocity within a vapor cavity 635.

In some embodiments, a deformable electrode may move within the materialit is incising with a piecewise velocity profile. That is, unlike atraditional rigid electrode, a portion of a deformable electrode mayadvance into a cavity (or “bubble”) created by a vaporization event tothen vaporize a new region of tissue before other regions along theelectrode have similarly advanced and thus allow for a velocitydistribution of instantaneous cutting velocities along the electrode.Such a deformable electrode may be kept under tension along its length,which may in turn cause the deformable electrode to advance throughtissue at a rate at least partially determined by an average cuttingrate and at least partially determined by a local cutting rate, whichmay be itself at least partially determined by the tension force on theelectrode. The mass (or a mass density) and/or the stiffness of adeformable electrode may at least partially dictate its ability toadvance into a cavity created by a vaporization event. An averagecutting rate may be affected by moving an electrode or electrodeassembly using a translation element (or “translation device”) and anactuator (e.g. along the x-axis, where +x may be defined as thedirection of the intended incision). By way of non-limiting example, atranslation element may be selected from the group consisting of: atranslation stage, a linear stage, a rotary stage, a rail, a rod, acylindrical sleeve, a screw, a roller screw, a travelling nut, a rack,pinion, a belt, a chain, a linear motion bearing, a rotary motionbearing, a cam, a flexure, a dovetail, and combinations thereof. As usedherein, the terms “stage” and “slide” are considered equivalent whenused to describe a translation element, device, or system. By way ofnon-limiting example, such actuators may be chosen from the groupconsisting of; a motor, a rotary motor, a squiggle motor, a linearmotor, a solenoid, a rotary solenoid, a linear solenoid, a voice coil, aspring, a moving coil, a piezoelectric actuator, a pneumatic actuator, ahydraulic actuator, a fluidic actuator, and combinations thereof.Alternately, the electrode assembly may be manually actuated.

In some embodiments, a tension may be chosen to accommodate thestiffness of the material being used to form an electrode, such as maybe represented by an elastic modulus. By way of non-limiting example, anelastic modulus may be chosen from the group consisting of: a flexuralmodulus, a Young's modulus, a bulk modulus, a section modulus, and ashear modulus. For a deformable electrode supported at least a singleend by a support structure, a modulus E of the electrode material may beused to determine a tension force F for an allowed deflection distance

${d = \frac{{FL}^{3}}{48{IE}}},$

where L is the unsupported length of the electrode and I is the secondmoment of inertia for the cross-sectional shape of the electrode; andmay be given by

$I = \frac{{bh}^{3}}{12}$

for a rectangular electrode, where w is the thickness of the electrodein the direction orthogonal to the deflection, and h the thickness ofthe electrode in the direction of deflection, such as may be equal to˜2r_(e) as described earlier herein. Similarly, second moment of acylindrical electrode, such as a wire, may be given by

${I = \frac{\pi r^{4}}{2}},$

where r represents the radius of said cylinder.

In some embodiments, there may be a tradeoff between a characteristicextent (i.e. a “dimension” or a “thickness” or a “size”) of an electrode(e.g. a diameter in the case of a wire or other such elongate electrode)and its corresponding mechanical stability, and therefore the strengthand ruggedness of an instrument constructed thereby, especially in asystem comprising a moving elongate electrode. Therefore, a thin wireelectrode stretched taught may provide for increased mechanicalstability over a slack thin wire electrode. Increased mechanicalstability may manifest increased incisional precision (e.g., such anelectrode may be less likely to drift transversely to the incisiondirection). An alternate embodiment may further comprise a tensioningelement mechanically coupled to the electrode provide for a nominallymore constant tension force on the electrode. A thin, deformableelongate electrode as described herein may be treated as the fundamentalmode of a simple harmonic oscillator, with a fundamental frequency (or,equivalently, a mechanical resonance frequency)

${f_{0} = {\frac{1}{2\pi}\sqrt{\frac{k}{m}}}},$

with k being the material stiffness and m the mass. The collapse of avapor cavity may cause said tensioned electrode to accelerate at leastpartially according to the tension provide and where the collapse of thecavity may be considered much like releasing a plucked string (i.e., theelectrode). A force F on such a tensioned deformable elongate electrodeadjacent to a cavity of extent z may then be understood as

${F = \frac{2{Tz}}{l}},$

where T is the tension on the electrode, 1 the unsupported length of theelectrode, and extent z may be a diameter of a nominally sphericalcavity, and z<<1. Similarly,

$f_{0} = {\frac{1}{\pi l}\sqrt{\frac{T}{2\mu}}}$

for a tensioned electrode with linear mass density μ, where

$\mu = \frac{{\pi\rho\varphi}^{2}}{4}$

and ρ=˜9*10³ k·gm⁻³ for pure tungsten. For example, considering a ˜Ø10μm nominally pure tungsten wire of unsupported length l=˜10 mm (i.e., amass of ˜7 μg, or a linear mass density μ (or, equivalently, a mass perunit length) of ∥0.7 μg·mm⁻¹) that is tensioned at T=−200 mN thepreceding relations may yield k=˜40 N·m⁻¹, f=˜12 kHz and a period ofτ=˜83 μs. Alternately, a ˜Ø5 μm nominally pure tungsten wire ofunsupported length l˜10 mm, ˜˜0.177 μg·mm⁻¹, and T˜100 mN may yieldf=˜17 kHz. Alternately, a ˜Ø19 μm nominally pure tungsten wire ofunsupported length l˜8 mm, μ˜2.55 μg·mm⁻¹, and 18 300 mN may yieldf=˜9.65 kHz. Alternately, a ˜Ø12.5 μm nominally pure tungsten wire ofunsupported length l˜3 mm, μ˜1.1 μg·mm⁻¹, and 18 300 mN may yieldf=˜39.1 kHz. Alternately, a ˜Ø200 μm nominally pure tungsten wire ofunsupported length l˜12 mm, μ˜282 μg˜mm⁻¹, and T˜1N may yield f=˜1 kHz.The force required to deform an elongate electrode may scale nonlinearlywith a characteristic cross-sectional distance of said electrode.

In this configuration such an electrode may be translated in thex-direction, and may be displaced (“plucked”) by x=˜20 μm to produce alocal peak velocity x′ of

${x^{\prime} = \left. \frac{20{\mu m}}{\frac{83\mu s}{4}}\rightarrow{\sim {1{}{m \cdot s^{- 1}}}} \right.},$

which may be constrained to motion predominantly along the incisiondirection, x-axis (i.e. parallel to the direction of electrodetranslation, or equivalently, transverse to an elongate direction) andthereby minimizing errors that are transverse to the intended incisiondirection. Such a configuration may provide for reduced thermal damageand/or reduced traction as compared to that of systems comprising ofrigid electrodes as primary heat deposition and/or thermal diffusion maybe relatively reduced by utilizing such a deformable electrode to bettermatch the tissue velocity. Such a deformable (or “flexible”) electrodemay move faster than its associated plasma incises tissue, as a localvelocity of said electrode may be inversely proportional to the sag onsaid electrode and said electrode may tend to follow the plasma torelieve an increased tension thereon and may move with velocitiesgreater than ˜1 ms⁻¹. In doing such, said electrode may be said to“flex” or “deform” or “vibrate.” As such, an elongate electrode, asdescribed herein, may vibrate (or, equivalently, “deform”, or,equivalently, “flex”) transversely to the elongate axis of theelectrode. By way of non-limiting example, the following table listsvarious configurations of electrode materials, sizes, and theircorresponding mechanical resonance frequencies.

In some embodiments, thermal confinement may be achieved if a dischargeis produced within a single cycle of a pulsatile voltage waveform, suchas within a nanosecond timeframe. From the field of laser-tissueinteraction we know that explosive vaporization by nanosecond pulses mayproduce a peak temperature of ˜200° C. and that the volume of theresultant void (or “crater” or “cavity”) may be ˜50% greater than thesubstantially heated volume. For example, photodisruption is known toproduce such damage volumes. The ejection of vapor and/or water and/ordebris from an incised region may preclude the formation of an arcdischarge between the electrode and its environment, even at hightemperatures; something which a thin deformable electrode mayintrinsically provide, especially should said deformable electrodecontact tissue along a region that is less than its circumference andproduce a void that is larger than the interaction volume, as wasdescribed regarding certain effects of photodisruptive nanosecond laserpulses. This extended damage volume may assist in the ejection of debrisand/or water and/or vapor. For example, the energy E required to raise a˜Ø10 μm sphere of water from ˜20° C. to ˜200° C. is E=ρc ΔT V→396 nJ.However, a bubble that is smaller than the extent of the electrode maynonetheless provide for a resultant cavity of sufficient extent to allowpassage of the entire electrode, such as may be the case with tissuecontact along only ˜1/2 to ˜2/3 of the electrode circumference (orequivalently, only ˜1/2 to ˜2/3 of the electrode diameter, asgeometrically projected onto said tissue) due to the increase in theresultant crater volume. The commensurate reduction in energy requiredto induce a plasma in this case may be

$\left. {E^{*} \sim {\frac{2}{3}E}}\rightarrow{114{nJ}} \right.$

and the extent of the resultant crater may be sufficient to accommodatethe entire ˜Ø10 μm electrode, as may be especially the case formechanically compliant tissues. By way of non-limiting example, a powerof ˜15 W may be delivered to an electrode at a pulse repetitionfrequency (“PRF”) of ˜1 MHz for an incision width of ˜10 mm (orequivalently, an average linear average power density of ˜1.5 W·mm⁻¹),providing ˜15 μJ of energy per cycle (or per “pulse”), for τ_(pulse)=1μs. For example, a ˜10 mm long, ˜Ø10 μm wire electrode operating asdescribed with PRF=˜1 MHz and E_(pulse)=˜15 μJ, an active ablationlength per pulse may observe the following relation,

${L_{a} = {\phi\frac{E_{pulse}}{E^{*}}}},$

and L_(a) may be ˜1.32 mm. Furthermore, L_(a) need not comprise a singlecontiguous length but may be comprised of separate instances of discreteablations or discrete ablation regions distributed along an entireelectrode length such that the individual lengths of said discontinuouszones (or, equivalently, non-overlapping regions) may sum to about thevalue of L_(a) per pulse. Said electrode may also be translated throughtissue at an active translation velocity (or “rate”) v_(a) that is atleast partially determined by L_(a), such as

$v_{a} \approx {{PRF}\frac{\phi}{2}{\frac{L_{a}}{L}.}}$

Continuing with the previous exemplary configuration, a total activelength of ˜1.32 mm along a ˜10 mm long, ˜Ø10 μm electrode may betranslated through tissue with an active translation velocity v_(a) of˜660 mm·s^(·1) to incise tissue while the electrode may deform as itincises and an actual local peak velocity of at least a single portionof said electrode may be different than v_(a) due to the velocity of anunderlying translation via an actuator, v_(t), as well as the elasticityof and tension applied to the electrode, as described elsewhere herein.That is, v_(t) need not be equal to v_(a). v_(t) may be chosen to bebetween ˜1 mm·s⁻¹ and ˜5000 mm·s⁻¹. Optionally, v_(t) may be chosen tobe between ˜10 mm·s⁻¹ and ˜1000 mm·s⁻¹. Optionally, v_(t) may be chosento be between ˜50 mm·s⁻¹ and ˜500 mm·s⁻¹. By way of non-limitingexample, a ˜10 mm long, ˜Ø13 μm tungsten wire under ˜300 mN of tensionoperating with PRF=˜1 MHz and E_(pulse)=˜15 μJ may be translated with apeak v_(t) of ˜300 mm·s^(·1) to incise corneal tissue with minimalcollateral damage. Considering the foregoing, a system may be configuredto allow the electrode velocity to nominally match the tissue velocityusing a moving front of plasma-induced bubbles along the length of adeformable electrode that is translated through a tissue to be incised.A variable velocity may be used, as is discussed elsewhere herein.

FIG. 4 shows a tensioned electrode assembly 5 may comprise tensioningelement 700, which in turn may be operatively coupled to electrode 702and affixed to electrode assembly 4 via attachments 704 & 706 such thattensioning element 700 allows electrode 702 to stretch (or “deform” or“flex” or “vibrate”) while in contact with tissue 2 (not shown in thepresent figure). The incisional portion of electrode 702 may compriseonly a portion of the conductive portion of electrode 702. Radii 708located atop arms 710 & 712 may provide a smooth surface for electrode702 while it stretches in order to avoid excessive strain as might beimparted at a sharper transition. Arms 710 & 712 may be considered to beat least a portion of a support structure intended to provide mechanicalstability to at least a portion of electrode 702. A gap may existbetween arms 710, 712, and may serve to receive tissue before and/orduring and/or after creating an incision, such as is shown in theinstant embodiment. In some embodiments, the electrode assembly 5comprises a support structure as described herein.

In some embodiments, a processor, e.g. a controller, is operativelycoupled to the elongate electrode to provide movement to the elongateelectrode. For example the processor can be configured with instructionsprovide to control the actuator and move one or components of theelectrode assembly. In some embodiments, the processor is configuredwith instructions to advance the electrode distally and draw theelectrode proximally, for example.

In some embodiments, the elongate electrode is sized for insertion intothe tissue, and the processor is configured with instructions to incisethe tissue with the electrode to define a volume of incised tissuewithin a pocket. While the volume can be configured in many ways, insome embodiments the volume comprises a shape profile, e.g. the shapeprofile of a lenticule. In some embodiments, the processor is configuredwith instructions to move the electrode with a first movement to definea first incised surface on a first side of the volume of tissue andmoved with a second movement to define a second incised surface on asecond side of the volume of tissue. In some embodiments, the processoris configured with instructions to advance the electrode distally todefine a first surface on a first side of the volume of tissue and todraw the electrode proximally to define a second surface on a secondside of the volume of tissue. In some embodiments, a gap extends betweenthe elongate electrode and the support structure and the gap is sized toreceive tissue such that tissue extending into the gap is incised whenthe electrode is drawn proximally.

In some embodiments, the movement of the electrode is coordinated withthe shape of one or more contact plates, in order to define the volumeof incised tissue. In some embodiments, the contact plate comprises afirst configuration to define a first surface on a first side of thevolume of tissue and a second configuration to define a second surfaceon a second side of the volume of tissue. In some embodiments, a firstcontact plate comprises a first shape profile to define a first surfaceon a first side of the volume of tissue and a second shape profile todefine a second surface on a second side of the volume of tissue, e.g.first and second surfaces of a lenticule comprising the volume oftissue. In some embodiments, the contact plate comprises a plurality ofactuators operatively coupled to the processor, and the processor isconfigured with instructions to shape the contact plate with a firstsurface profile for a first incision, and to shape the contact platewith a second profile for a second incision. In some embodiments,processor is configured with instructions to shape the contact platewith the first profile, incise the first side with the first shapeprofile, shape the contact plate with the second profile, and incise thesecond side with the second profile, with a total time of no more thanabout 10 s, for example no more than 5 s, or no more than 2 s, forexample.

A support structure may be fabricated, at least partially from amaterial that is selected from the group consisting of: tungsten,nitinol, steel, copper, brass, titanium, stainless steel,beryllium-copper alloy, cupronickel alloy, palladium, platinum,platinum-iridium, silver, aluminum, polyimide, PTFE, polyethylene,polypropylene, polycarbonate, poly(methyl methacrylate), acrylonitrilebutadiene styrene, polyamide, polylactide, polyoxymethylene, polyetherether ketone, polyvinyl chloride, polylactic acid, glass, ceramic, andcombinations thereof. Tensioning element 700 may be connected directlyto at least a portion of electrode assembly 4 as shown, or alternatelyto a at least a portion of a subsequent element to which electrodeassembly 4 is attached; such as coupler 52 or electrode assembly mount17. By way of non-limiting example, tensioning element 700 may be aspring, a coil spring, a leaf spring, a torsion spring, an elastic mesh,a hinge, a living hinge, and combinations thereof. A deformableelectrode may be supported by a support structure and allowed to deformwhile creating a plasma-induced incision within a target tissue ortarget tissue structure. An electrode (e.g. electrode 702, or portionsthereof) may be at least partially composed of a material selected fromthe group consisting of: tungsten, nitinol, steel, copper, brass,titanium, stainless steel, beryllium-copper alloy, cupronickel alloy,palladium, platinum, platinum-iridium, silver, aluminum, andcombinations thereof. Alternately, an electrode may comprise a wirecomposed of the same materials just listed. Alternately, an electrodemay be coated in certain areas to preclude conduction and/or incision insaid areas. Alternately, tubing may be used in lieu of a coating toinsulate areas of an electrode. Such a coating or tubing may be selectedfrom the group consisting of: polyimide, PTFE, polyethylene,polypropylene, polycarbonate, poly(methyl methacrylate), acrylonitrilebutadiene styrene, polyamide, polylactide, polyoxymethylene, polyetherether ketone, polyvinyl chloride, polylactic acid, glass, ceramic, andcombinations thereof. An electrode (e.g. electrode 702) may be a wirehaving a diameter between ˜3 μm and ˜300 μm. Alternately, said wire mayhave a diameter between ˜10 μm and ˜50 μm. Alternately, said wire mayhave a diameter between ˜12 μm and ˜17 μm. Tensioning element 700 may beconfigured to provide tension of such that the resultant force on anelectrode is ˜80% of a rated or measured yield strength of the electrodeor its material; such as may be the case for a tungsten wire of ˜Ø12.5μm loaded with a tension of ˜295 mN, which may also correspond to anelongation of ˜0.5%. Optionally, a tensional force may be between ˜50%and ˜95% of a yield strength. Optionally, a tensional force may bebetween ˜70% and ˜85% of a yield strength. Other configurations may bescaled using the relationships relating to the second moment of inertia,as described earlier herein with respect to allowable deflectiondistances (e.g. ˜80% of a rated yield tension force of ˜4.7N, or ˜3.8N,for a nominally pure tungsten wire with a diameter of ˜Ø25 μm. Coupler52 may be operatively coupled to cutting electrode mechanism 502 viacoupler 74. By way of non-limiting example, coupler 74 may be areceptacle configured to accept a disposable module comprised ofelements electrode 4, coupler 52, and electrode mount 17 and whereinelectrode mount 17 comprises mating features compatible with those ofcoupler 74 such as threads, a clasp, a snap fitting, and combinationsthereof. Cutting electrode mechanism 502 may further comprise matingfeatures compatible with those of couplers 71 & 72, which are themselvesmechanically coupled to actuators 50 & 504, respectively, and mayprovide axes of motion to move electrode assembly 4 to create anincision in tissue 2 (not shown). Alternately, by way of non-limitingexample, elements electrode 4, coupler 52, electrode mount 17, cuttingelectrode mechanism 502, and coupler 74 may be packaged into a probebody 26 as a disposable module configured to engage with a more completeincisional system to actuate said electrode or electrode assembly orprobe assembly along axis of motion 12. Although not shown for clarity,at least potions of probe body 5, including tensioned electrode assembly5, maybe made to move using a translation element to ensure mechanicalstability and accuracy along at least a single direction of motion.

FIG. 5 shows a tensioned electrode assembly 5 similar to that of FIG. 4, wherein radii 708 may further comprise channels 720 into whichelectrode 702 may be placed to minimize positional errors due tounintentional electrode movement, especially that which is transverse tothe intended incision direction. Tensioning element 700 may beconfigured as a living hinge (or hinges, as shown) within or along arms710 & 712. Arms 710 & 712 may be comprised of a notched rigid material,as shown to provide living hinge 722. By way of non-limiting example, asuitable material for creating a living hinge may be selected from thegroup consisting of: polyethylene, polypropylene, polycarbonate,poly(methyl methacrylate), acrylonitrile butadiene styrene, polyamide,polylactide, polyoxymethylene, polyether ether ketone, polyvinylchloride, copper beryllium, and combinations thereof. In the case whereliving hinge 722 is integral to an arm 710 or 712 and an electricallyconductive material may be chosen and such cutting electrode may besoldered, brazed, adhered with an electrically conductive adhesive,and/or welded to the arm(s). In the case where a living hinge isintegral to an arm 710 or 712 and an electrically insulating material ischosen, electrode 702 may be otherwise adhered to the arm, or besoldered, brazed, and/or welded to an adjacent conductive material.

FIG. 6 shows a system to incise tissue; such as ocular tissue, includingcorneal, limbal, and stromal tissue, system 800. System 800 may comprisea tensioned electrode assembly 5 similar to that of FIGS. 4 & 5 .Electrode assembly 4 may be coupled to electrode mount 17 via coupler52. By way of non-limiting example, coupler 52 may be made to be atleast partially electrically insulated. Electrode assembly 4 maycomprise arms 710 & 712, electrode 702, and tensioning element 700,which may be operatively coupled to electrode 702 and affixed viaattachments 704 & 706 to create tensioned electrode assembly 5 such thattensioning element 700 may allow electrode 702 to stretch while incontact with tissue 2. Attachments 704 and/or 706 may be achieved viasoldering, brazing, adhering, compression fitting, clamping, andcombinations thereof. Radii 708 located atop arms 710 & 712 may providea smooth surface for electrode 702 while it stretches in order to avoidexcessive strain as might be experienced at a sharper corner. Tensioningelement 700 may be connected directly to an electrically conductiveportion of electrode 4, or alternately to a subsequent element to whichto comprise electrode 702; such as coupler 52 or electrode mount 17. Anincision may be made by moving along axis of motion 12. In the instantexemplary configuration, tensioned electrode assembly 5 may be comprisedof elements 700, 702, 704, 706, 708, 710, and 712; all of which may beat least partially constructed from an at least a partially conductivematerial and thus may be held at about the same voltage by driver 18(not shown) and all of which may be considered to comprise tensionedelectrode assembly 5. Alternately, electrode assembly 4 and tensionedelectrode assembly 5 may be the same. Alternately, some of theaforementioned elements may be comprised at least partially of anelectrically insulating material and thus may not be at the sameelectrical potential as the other elements comprised of at leastpartially electrically conductive material and electrode assembly 4 maybe considered to be only those elements comprising an at least partiallyelectrically conductive material and be a subsystem of an tensionedelectrode assembly 5, as shown. By way of non-limiting example,tensioning element 700 may be a spring, a coil spring, a leaf spring, atorsion spring, an elastic mesh or web, a hinge, a living hinge, andcombinations thereof. A torsion spring may be such as that found in astaple remover. By way of non-limiting example, an at least partiallyelectrically conductive electrode material may be selected from thegroup consisting of: tungsten, nitinol, steel, copper, brass, titanium,stainless steel, beryllium-copper alloy, cupronickel alloy, palladium,platinum, platinum-iridium, silver, aluminum, and combinations thereof.Alternately, an electrode 702 may be at least partially comprised a wirecomposed of the same material. Alternately, an electrode assembly 4 maybe at least partially comprised of elements composed of electricallyinsulating materials. Alternately, an electrode assembly 4 may be coatedin certain areas to preclude conduction and/or incision in said areas.Similarly, tubing may be used in lieu of a coating to insulate areas ofan electrode assembly. By way of non-limiting example, such a coating ortubing may selected from the group consisting of: polyimide, PTFE (e.g.,Teflon), polyethylene, polypropylene, polycarbonate, poly(methylmethacrylate), acrylonitrile butadiene styrene, polyamide, polylactide,polyoxymethylene, polyether ether ketone, polyvinyl chloride, polylacticacid, glass, ceramic, and combinations thereof. A return electrode (notshown) may be placed on or near the eye of the patient and connected todriver 18. A serial load of between ˜150Ω and ˜500Ω may be placedin-line with the electrode in order to provide for current limitation.Coupler 52 may be operatively coupled to cutting electrode mechanism 502via coupler 74. Alternately, by way of non-limiting example, elementselectrode 4, coupler 52, electrode mount 17, cutting electrode mechanism502, coupler 74, or a subset thereof may be packaged into a probe body26 as a disposable module configured to engage system 800 via couplers71 & 72, which in turn may comprise mating features compatible withthose of actuators 50 & 504, respectively; such as threads, a clasp, asnap fitting, and combinations thereof. Actuator 504 may provide an axisof motion (or equivalently, a “translation” along a direction of motion,e.g. axis of motion 14) be coupled to position encoder 51 via connection53 and both position encoder 51 and actuator 50 may be connected to atranslation device and/or actuator driver 57 via connections 55 & 59,respectively. By way of non-limiting example, connections 55 & 507 maycomprise at least one of the following, a mechanical coupler, anelectrical coupler, a magnetic coupler, and an optical coupler. Actuator504 may also provide an axis of motion (e.g. axis of motion 12) and becoupled to position encoder 506 via connection 505 and both positionencoder 506 and actuator 504 may be connected to actuator driver 508 viaconnections 509 & 511, respectively. It should be noted that only asingle axis of motion may be relied on to practice certain embodimentsof the present disclosure, such as in the creation of a corneal flaputilizing a single incision. The axes of motion for actuators 50 & 504,axes of motion 14 & 12, respectively, may be configured to be orthogonalor at least not colinear. Actuators 504 & 50 may be configured toactuate tensioned electrode assembly 5, or portions thereof, along axesof motion 12 & 14. Position encoders 51 & 506 may be mechanicallycoupled, via connections 55 & 507, respectively, to the module ontowhich electrode assembly 4 is mechanically coupled in order betterprovide reliable position information than non-collocated sensors mayprovide. Alternately, Actuator 50 may be configured to correspond to(or, “move along”) axis of motion 14 and be made to actuate (or“translate”) a contact plate 804 and connection 55 may be made withcontact plate 804, or structure supporting contact plate 804. Driver 18may be configured to provide controlled voltage and/or controlledcurrent to electrode 4. Driver 18 may provide an alternating voltageand/or current waveform to electrode 702. The type of such a waveformmay be, by way of non-limiting examples; selected from the groupconsisting of: pulsatile, sinusoidal, a square, sawtooth, triangular,fixed frequency, variable frequency, and combinations thereof. Driver 18may be configured to supply a waveform with a peak-to-peak full rangevoltage of between ˜50V and ˜1000V. Alternately, driver 18 may beconfigured to supply a waveform with a peak-to-peak full range voltageof between ˜200V and ˜500V. Driver 18 may be configured to supply awaveform with a carrier (or “base”) frequency of between ˜10 kHz and ˜10MHz. Alternately, driver 18 may be configured to supply a waveformfrequency of between ˜500 kHz and ˜2 MHz. Alternately, driver 18 may beconfigured to supply a waveform frequency of between ˜800 kHz and ˜1.2MHz. A burst duration may also be used and may further depend on theelectrode velocity, v_(t). Driver 18 may be further modulated tocomprise bursts of pulses at a modulation frequency of between ˜100 Hzand ˜3 MHz to create a duty cycle. The duty cycle may be between ˜0.01%and ˜100%. Alternately, the duty cycle may be between ˜50% and ˜100%.Alternately, the duty cycle may be between ˜95% and ˜100%. Driver 18 maybe configured to supply an average power of between ˜1 W and ˜25 W.Alternately, driver 18 may be configured to supply an average power ofbetween ˜12 W and ˜18 W. Driver 18 may be configured to supply an energyper cycle (or, equivalently, an “energy per pulse”) of between ˜1 μJ and˜100 μJ. Alternately, driver 18 may be configured to supply an energyper cycle of between ˜5 μJ and ˜50 μJ. Alternately, driver 18 may beconfigured to supply an energy per cycle of between ˜10 μJ and ˜20 μJ.

In some embodiments, a flap may be described as an incision yielding a“flap” of tissue that maybe lifted and pivot on a “hinge” to provideaccess to the tissue beneath it. By way of non-limiting example, cuttinga segment of tissue to depth of 130 μm and razing a plane at that depthbeneath a tissue surface may yield a flap with an uncut edge as itshinge. A flap may be amputated by completing the uncut edge of theexemplary incision. In some embodiments, a pocket may be described as anincision that separates a first depth (or layer) of tissue from a seconddepth (or layer) of a segment of tissue without necessarily creating aflap. By way of further non-limiting example, cutting one side of atissue to a depth and razing a plane at that depth beneath a tissuesurface may yield a pocket.

In some embodiments, significant drops of the input impedance of driver18 due to plasma discharge at electrode 702 may cause local currentspiking, which in turn may destroy the electrode and/or cause damagetissue. The power delivered (or, equivalently “delivered power”, orequivalently “maximum power output”) to the electrode may be limitedinstead to avoid such situations. An average power suitable forpracticing embodiments of the present disclosure may be between ˜1W·mm⁻¹ ˜10 W·mm⁻¹, especially during glow discharge. The delivered powermay be higher during the initial exposure to better ensure commencementof dielectric breakdown. Alternately, a voltage and/or current waveform(or alternately, a power control signal) used to power said electrode702 may be further modulated, or adjusted, such that it is proportionalto the instant or expected length of tissue engagement and/or theelectrode translation velocity, v_(t).

By way of non-limiting example, when incising a cornea, a voltage may beincreased from an initial value that corresponds to when electrode 702is about to initially engage, or initially engages, or is expected toinitially engage the tissue and is nominally directed towards a regionof more central cornea to a higher voltage that corresponds to whenelectrode 702 is traversing or expected to traverse the central corneaand thus have a relatively greater length of tissue engagement than itdid initially; said electrode voltage may be then made to decrease aselectrode 702 continues traversing cornea 2 and incising tissue withinherently less engagement length, said decrease may be configured to bethe opposite of the initial increase, but need not be. The position ofan electrode 702 within a cornea 2 may be inferred using an encoder inthe translation subsystem, as described elsewhere herein. In anembodiment, the voltage provided by driver 18 may be configured todeliver a maximum peak-to-peak bipolar nominally sinusoidal voltage of˜500V (comprising both ˜+250V and ˜−250V amplitudes, relative to anominal neutral voltage, which need not be a ground voltage) with a PRF(or “carrier frequency”) of ˜1 MHz that may ramp from ˜0V to maximumamplitude during the initial ˜50 μs of a translation and then may rampback to ˜0V during the final ˜100 μm of a translation, such as may beuseful when tensioned electrode assembly 5 is comprised of an ˜10 mmlong, ˜Ø10 μm, ˜99.99% pure tungsten wire for the incisional portion ofelectrode 702 that is tensioned to ˜300 mN by tensioning element 700 andtranslated at a maximum rate of ˜300 mm·s⁻¹ along direction 12 with aconstant acceleration of ˜2,000 mm·s⁻² with an initial electrodelocation that is between ˜4 mm and ˜7 mm from the closest aspect of thetarget tissue to be incised. It is to be noted that such a constantacceleration may yield a linear velocity profile in which an electrodemay be brought to rest inside of the target tissue, such as may berequired to create a flap or a lenticule as opposed to a completeincision, as will be described elsewhere herein.

In some embodiments, monitor 514 may be configured to monitor thevoltage and/or current supplied to electrode assembly 4 via connection516 and provide data regarding said voltage and/or current to driver 18via connection 518. The data regarding voltage and/or current ofelectrode assembly 4 may be in the form of signals from a comparator.System controller 60 may be operatively coupled to driver 18 viaconnection 62, which is at least a unidirectional connection.Alternately, connection 62 may also be a bidirectional connectionwherein controller 60 is able to sense and/or respond to at least asignal from driver 18. Signals from monitor 514 may be also provided tosystem controller 60 and acted upon thereby to control the incisioncreated by electrode assembly 4. Monitor 514 may reside within systemcontroller 60, and/or communicate with system controller 60 via driver18. Such a signal may be a safety signal related to a sensed voltage orcurrent, such as when said voltage or current is outside of prescribedbounds. In a further alternate embodiment, driver 18 and/or monitor 514may provide feedback to controller 60 or use such feedback internally.Such feedback may be, by way of non-limiting example, EMF or currentfeedback and may be useful in determining when electrode assembly 4contacts tissue and/or the status of the plasma. Such status may be, forexample, whether or not the plasma in the glow discharge regime or not.Connection 65 connects controller 60 with actuator 50 and is at least aunidirectional connection. Actuator 50 may be comprised of at least oneelectrical motor and may further comprise a positional encoder.Connection 65 may alternately be a bidirectional connection whereinsignals are shared between controller 60 and actuator 50, such asposition, velocity, acceleration, out of bounds errors, etc. In afurther alternate embodiment, actuator 50 may provide feedback tocontroller 60 or use such feedback internally and may share suchfeedback as signals with controller 60. Such feedback may be, by way ofnon-limiting example, force feedback and may be useful in determiningwhen electrode assembly 4 contacts tissue or when it imparts excessiveforce on the tissue to be incised. Likewise, connection 67 connectscontroller 60 with power supply 70 and is at least a unidirectionalconnection. In a further alternate embodiment, power supply 70 mayprovide feedback to controller 60 or use such feedback internally andmay share such feedback as signals with controller 60. Such feedback maybe, by way of non-limiting example, an error signal. Such error signalsmay be temperature errors, input voltage errors, output voltage errors,input current errors, output current errors, etc. Likewise, connection68 connects controller 60 with user interface 80 and is at least aunidirectional connection from user interface 80 to controller 80. In afurther alternate embodiment, user interface 80 may provide feedback tocontroller 60 or use such feedback internally and may share suchfeedback as signals with controller 60. For example, user interface 80may be a graphical user interface or a button or a foot pedal used tosignal actuator 50 to move electrode assembly 4 and incise tissue.Actuator drivers 57 & 508 may be connected to system controller 60 viaconnections 65 & 510, respectively. User interface 80 may be connectedto system controller 60 via connection 68 and user instructions senttherethrough.

In some embodiments, the system controller 60 comprises a processorconfigured with instructions to determine a profile of tissue to beremoved from the eye to provide refractive correction. The processor canbe configured to determine the shape profile of one or more plates usedto provide a refractive correction for the patient. Also althoughreference is made to controller 60, controller 60 may comprise acomponent of a distributed computing system and may be operativelyconnected to one or more processors as described herein, such as adistributed processing system.

In some embodiments, system 800 may further comprise contact plate 804,a support element 802, a suction element 810, and accompanying vacuumapparatus which may be used to fixate a contact tissue 2. An incision 42may be made in tissue 2 (the cornea and/or corneal stroma in the instantexemplary embodiment) by moving at least portions of tensioned electrodeassembly 5 along axis of motion 12 to create bed 43 using actuator 504.A contact plate 804 may be incorporated to applanate the cornea bymoving it onto the anterior surface of the cornea along axes of motion14 by means of actuator 50. Contact plate 804 may further comprise acontact surface 806 (not shown). Said contact plate 804 may be used toapplanate the cornea, especially when contact surface 806 is nominallyabout planar. By way of non-limiting example, contact plate 804 may beconfigured to be a planar glass window to allow visibility therethrough.By way of non-limiting example, contact plate 804 may be composed of amaterial selected from the group consisting of: glass, crystalline,ceramic, metal, polymer, and combinations thereof. A contact element 808(not shown) may be placed on the distal surface of contact plate 804 toprovide a clean and/or sterile surface for contact with tissue 2 and maybe configured as a thin, conformal, peel-and-stick sterile barrier,which may also be disposable. By way of non-limiting example, contactelement 808 may be composed of a material selected from the groupconsisting of: polyethylene (PE), polyvinylchloride (PVC), polypropene(PP), oriented PP (OPP), biaxially oriented PP (BOPP), polyethyleneterephthalate (PET), and combinations thereof. Contact plate 804 may besupported, at least in part, by support 802. Support 802 may further atleast partially support elements of tensioned electrode assembly 5, suchas arms 710 & 712 and thereby also supporting electrode 702 andtensioning element 700 to form a at least a portion of electrodeassembly 4 and tensioned electrode assembly 5. As such, arms 710 & 712may be considered to be a support structure for electrode 702.Alternately, support 802 may be operatively coupled to probe body 26and/or sheath 6. Alternately, contact plate 804 may be made to movealong with support 802 relative to tissue 2. A suction element 810 maybe used to stabilize the eye containing tissue 2 relative to contactplate 804 and/or electrode 4. Suction element 810 may be configured as anominally open annular ring, as shown, or alternately by any otherapplicable construction to achieve fixation to the eye, such as a singleopen pocket, or a plurality of open pockets. Suction element 810 may beoperatively coupled to vacuum pump 850 via vacuum line 870 to provide anegative pressure within suction element 810. For patient safety andsystem reliability, a vacuum switch 852 and/or a vacuum sensor 854 maybe placed in between suction element 810 and vacuum pump 850, andconnected via connections 860 and 862, respectively. System controller60 may be connected to vacuum pump 850, vacuum switch 852, and vacuumsensor 854 via electrical connections 864, 866, and 868, respectively.In the instant configuration, actuator 50 may be configured tocorrespond to axis of motion 14 and be made to actuate (or “translate”)a contact plate 804 and connection 55 may be made with contact plate804, or such structure supporting contact plate 804. Contact plate 804may be translated at a rate, or velocity of between ˜0.1 mm·s⁻¹ and˜1000 mm·s⁻¹, and in an alternate embodiment it may be translated at arate of between ˜10 mm·s⁻¹ and ˜100 mm·s⁻¹. The motion corresponding toactuator 50 may be configured to be at least partially simultaneous withof actuator 504, or the velocity profiles thereof.

In some embodiments, system 800 may be further configured such that atensioned electrode assembly 5 that at least partially comprises anelectrode 702. Electrode 702 may comprise a tungsten wire of ˜12.5 μm indiameter and at least ˜99% purity that runs across arms 710 & 712 toform a bridge distance of ˜12mm and uses a mechanical coil springimparting a tensional force of ˜300 mN on electrode 702, for example.

In some embodiments, an incision may form a flap or a pocket orcombinations thereof based upon whether or not the electrode cuttingwidth is about greater than or about equal to the lateral extent of thetarget tissue structure to be incised and whether or not the electrodeis made to penetrate outwards laterally from the tissue. That is, a flapmay be made in an anterior aspect of a cornea by applanating orotherwise compressing said anterior corneal surface using contact plate804 to yield a lateral dimension for incision 42 of between ˜3 mm and˜11 mm, or alternately of between ˜8 mm and ˜10 mm, all of which may beless than the aforementioned bridge distance to provide a flap incision.A flap incision may be configured to provide a D-shaped incision 42, asshown, where the straight segment of the D-shaped incision may be ahinge portion. Similarly, a pocket incision may be made if the electrodebridge distance is less than the lateral extent of the compressed corneapresented to the electrode. Alternately, a combination flap/pocketincision may be created using a pocket incision configuration andallowing the electrode to traverse the entire distance through thecornea and may yield an incision shaped as a fully-rounded rectangle, ora partially-rounded rectangle (e.g. when configured to comprise astraight uncut portion). In an alternate embodiment, driver 18 may beconfigured to supply a sinusoidal waveform that may have a peak-to-peakfull range voltage of ˜250V at a frequency of ˜1 MHz and a power limitof ˜15 W to incise corneal tissue at an electrode translation rate ofbetween ˜200 mm·s^('1) and ˜0 mm·s⁻¹ (i.e. v_(i)=˜0 mm·s⁻¹ whileelectrode is stopped at end of incision) along direction of motion 12and utilizing steps 102 through 122 of flowcharts 100 & 200, as shown inFIGS. 7 & 9 . Step 202 of flowchart 200 may be utilized for thediscontinuation of power to an electrode in coordination with the motionof the electrode and contact plate 804 such that the electrode isprovided a voltage of nominally -OV during the interim period betweenthe electrode moving in a first direction and then moving in a seconddirection, such as might be the case if contact plate 804 is moved alongdirection of motion 14 in order to remove a portion of tissue (e.g. a“lenticule” of intrastromal tissue). Alternately, the electrode voltageand/or power may be made a function of the electrode velocity, and/orposition, and/or cutting extent, as described elsewhere herein.

Alternately, a variable acceleration may be utilized to create a motionprofile for an electrode, resulting in a nonlinear velocity profile.Such a motion profile may require a higher order control model andincorporate “jerk” and/or “snap” and/or “crackle” and/or “pop” factorsto provide an asymmetrical acceleration/deceleration such that the rangeof v_(t) in the initial ˜50 μs is similar to that of the final ˜10 μs,by way of non-limiting example.

The velocity and/or velocity profile and/or the active incision widthmay be taken into account when controlling (e.g., “modulating”) thepower to the electrode.

By way of non-limiting example, the power to an electrode 702 may beadjusted by choosing a maximum value of a parameter selected from thegroup consisting of: a voltage, a current, a carrier frequency, amodulation frequency, a duty cycle, a power setpoint, a power limit, anenergy per pulse setpoint, an energy per pulse limit, and combinationsthereof.

By way of non-limiting example, a modulation relationship describing thecontrolled power output of an electrode 702 driven by driver 18 may beselected from the list comprised of the following; a fixed relationship,a constant relationship, a linear relationship, a nonlinearrelationship, a logarithmic relationship, a sinusoidal relationship, anexponential relationship, a polynomial relationship, and combinationsthereof. Said relationships may be direct or inverse, depending upon theimmediate system configuration and determinable using the descriptionsand equations included herein. Said controlled power output may beconsidered to be the instantaneous power and/or the average power and/orthe peak power. Said modulation may be achieved via control of driver18, by way of non-limiting example. The term modulation is used hereinto indicate an alteration of an otherwise consistent output, waveform,or signal. As used herein, “modulating” a waveform is equivalent to“enveloping” a waveform and “modulation envelope” is equivalent to“envelope.” Alternately, no modulation may be used to envelope awaveform, including an intrinsically pulsatile waveform.

By way of non-limiting example, when creating a corneal flap incision, aduty cycle D_(c) may be modulated by utilizing a compound relationshiprepresenting the active incision width y_(a) which may be modeled as achord length of a circle of radius R that is turn a function of thedistance into the target tissue x_(c) (i.e., the height of the circularcap) multiplied by the velocity profile v_(t) to yieldD_(c)∝v_(t)y→2v_(t)[x_(c)(2R−x_(c))]^(1/2), which may be normalizedusing the nominal values for R and v_(t,max) to provide a genericenvelope function.

Alternately, the voltage U required for vaporization may be regarded asU=r_(e)√{square root over (ρCΔTγ/τln(l/r_(e)))}, and at least acomponent of a modulation relationship for electrode voltage V providedby driver 18 to an electrode 702 may be V∝√{square root over(ln(y_(a)))}→2√{square root over (x_(c)(2R−x_(c)))}/√{square root over(2)}. It should be noted that the preceding examples at least partiallyinvolve exponential relationships, as the radical is the inversefunction to the of taking of a power.

Alternately, an energy per cycle provided by driver 18 to an electrode702 may be configured to deliver an energy per cycle that may be atleast partially dependent on the value of v_(t) and/or at leastpartially dependent on the value of the active incision width y_(a).

Alternately, a duty cycle provided by driver 18 to an electrode 702 maybe configured to deliver a duty cycle that may be at least partiallydependent on the value of v_(t) and/or at least partially dependent onthe value of the active incision width y_(a).

Alternately, a voltage provided by driver 18 to an electrode 702 may beconfigured to deliver a voltage that may be at least partially dependenton the value of v_(t) and/or at least partially dependent on the valueof the active incision width y_(a).

Alternately, a current limit provided by driver 18 to an electrode 702may be configured to deliver a current limit that may be at leastpartially dependent on the value of v_(t) and/or at least partiallydependent on the value of the active incision width y_(a).

Alternately, a power limit or setpoint provided by driver 18 to anelectrode 702 may be configured to deliver a power limit or setpointthat may be at least partially dependent on the value of v_(t) and/or atleast partially dependent on the value of the active incision widthy_(a).

Alternately, a PRF provided by driver 18 to an electrode 702 may beconfigured to deliver a PRF that may be at least partially dependent onthe value of v_(t) and/or at least partially dependent on the value ofthe active incision width y_(a).

Alternately, v_(t) may be at least partially dependent upon the activeincision width y_(a) and/or x_(c), where y_(a)=2√{square root over(x_(c)(2R−x_(c))}, as described elsewhere herein.

Alternately, such as may be useful when tensioned electrode assembly 5is comprised of an ˜10 mm long, ˜Ø20 μm, ˜99.99% pure tungsten wire forthe incisional portion of electrode 702 that is tensioned to ˜300 mN bytensioning element 700 and translated at a maximum rate of ˜200 mm·s⁻¹along direction 12 with a constant acceleration of ˜1,000 mm·s⁻² with aninitial electrode location that is between ˜2 mm and ˜4 mm from theclosest aspect of the target tissue to be incised (i.e., the pointnearest the electrode along its axis of motion), a voltage provided bydriver 18 may be configured to deliver a maximum peak-to-peak bipolarnominally sinusoidal voltage of ˜600V (comprising both ˜+300V and ˜−300Vamplitudes, relative to a nominal neutral voltage) with a PRF (or“carrier frequency”) of ˜1 MHz that linearly ramps from ˜0V to maximumamplitude during the initial ˜50 μs of a translation and ramps back to˜0V during the final ˜50 μs of a translation.

In a further alternate embodiment, a duty cycle provided by driver 18may be configured to deliver a duty cycle that ramps from ˜0% to maximumamplitude of between ˜70% and ˜100% during the initial ˜50 μs of atranslation and ramps back to ˜0% during the final ˜10 μs of atranslation. Said duty cycle may be created utilizing a modulationfrequency, such as a square-wave gating function. Sais square-wavegating function may be configured to have variable “on” and/or “off”times. The relationship of the variable “on” and/or “off” times may beas described elsewhere herein regarding the relationships for describingthe controlled power output of an electrode.

In a further alternate embodiment, a duty cycle provided by driver 18may be configured to deliver a duty cycle that may be at least partiallydependent on the value of v_(t) and may ramp from ˜0% to maximumamplitude of between ˜70% and ˜100% while the velocity of the electrodeis increased from rest (i.e. v_(t)=0 mm·s⁻¹) to its maximum value andthe duty cycle is then decreased to ˜0% when the electrode velocity isreduced back to rest.

In a further alternate embodiment, the maximum power output provided bydriver 18 may be configured to deliver a maximum power output that isthat may be at least partially dependent on the value of v_(t) and mayramp from ˜0% to maximum amplitude of between ˜70% and ˜100% while thevelocity of the electrode is increased from rest to its maximum valueand the maximum power output is then decreased to ˜0% when the electrodevelocity is reduced back to rest.

In a further alternate embodiment, a voltage provided by driver 18 maybe configured to deliver a voltage that may be at least partiallydependent on the value of v_(t) and may ramp from ˜0% to maximumamplitude of between ˜70% and ˜100% while the velocity of the electrodeis increased from rest to its maximum value and the duty cycle thendecreased to ˜0% when the electrode velocity is reduced back to rest.

FIG. 7 describes a method of incising tissue. Flowchart 100 comprisessteps 102-122 that may be completed serially, or in any suitable order.At a step 102 an eye is selected for treatment. Step 104 involvesactivating the system, and step 106 involves positioning a probe ontothe tissue to be treated. Step 108 involves activating a vacuum systemto fixate tissue with respect to the probe (such as via the vacuumsystem described earlier). Step 110 involves positioning a contact plateonto the tissue in a first position. Step 112 involves power beingapplied to an electrode. Step 114 involves translating (or “moving” or“actuating”) said electrode in a first direction (such as along axis ofmotion 12, the “+x-direction”). Step 116 involves discontinuing power tothe electrode. Step 118 involves disengaging the vacuum fixation andfreeing the tissue and disengaging the eye being treated. Step 120involves an electrode disengaging from a tissue just incised. Step 122involves deactivating the system and disengaging it from the eye. A thinelectrode may be allowed to break as the system is disengaged from thepatient. Alternately said electrode may be made to translate in a seconddirection, nominally opposite of said first direction. Alternately, step108 and step 110 can be exchanged and power applied to the electrodeonce it is in contact with tissue 2. Alternately, steps 116 through 120may be eliminated to create an excision. Alternately, steps 116 & 118may be eliminated if there is only low risk of collateral damage due totissue heating while the actuator changes direction. Alternately, step116 may involve a tapered reduction in power to the electrode, and step112 may involve a tapered increase in power to the electrode, asdescribed elsewhere herein.

Although FIG. 7 shows a method of incising tissue in accordance withsome embodiments, one of ordinary skill in the art will recognize thatmany adaptations and variations can be made in accordance with thepresent disclosure. For example, the steps can be performed in anysuitable order, some of the steps repeated, some of the steps omitted,and combinations thereof.

In some embodiments, a processor as described herein is configured withinstructions to perform one or more of the steps of the method of FIG. 7.

FIGS. 8A through 8D are directed at details in accordance withembodiments of the present disclosure, wherein a tensioned electrodeassembly 5 is now shown in a view orthogonal to that of FIGS. 4 through6 , such that axis of motion 12 may now be into and out of the plane ofthe figure, while axis of motion 14 may be vertical, and wherein thesteps of FIG. 7 may be followed. FIG. 8A shows that contact plate 804may be configured to lie within a middle portion of support 802 and moverelative to support 802 along axis of motion 14. Contact surface 806 ofcontact plate 804 may be about planar and about parallel to the cuttingportion of electrode 702. Electrode 702 is shown as being initiallybehind the cornea in this view. Contact element 808 may be placed oncontact surface 806 to create a sterile disposable for use only during asingle procedure. Contact element 808 may nominally conform to at leasta portion of contact surface 806. The portion of contact surface 806 towhich contact element 808 conforms may be a center portion. Suctionelement 810 may be configured to contact the eye containing tissue 2 ata region nearby the outer cornea and/or the corneoscleral limbus 838, asshown, to fixate and stabilize cornea 843 (not indicated in the presentfigure). Alternately, suction element 810 may be made to contact atleast an aspect of cornea 843 to better stabilize tissue 2 relative tothe incision of electrode 702. Cornea 843 may comprise anterior cornealsurface 842 and posterior corneal surface 844. In this instance, targettissue 2 may be considered to be stromal tissue within cornea 843 andcontained between anterior corneal surface 842 and posterior cornealsurface 844. Intraocular lens 840 is shown for the purposes oforientation and may be a natural lens or a prosthetic lens. In thepresent embodiment, contact element is in contact with the apex ofanterior corneal surface 842 of cornea 843. Electrode assembly 4 maycomprise arms 710 and 712, as well as electrode 702, as shown. Theconfiguration of the immediate figure may represent steps 102, 104, and106 of FIG. 7 .

FIG. 8B shows the system of FIG. 8A, wherein contact plate 804 andtherefore contact element 808 may have been moved farther along axis ofmotion 14 to applanate cornea 843 and tissue 2 therein. Electrode 702may be made to incise tissue 2 by traversing a path along axis of motion12, as has been described elsewhere herein, to create incision 45 andthereby bed 43 (not indicated in this view). The configuration of theimmediate figure may represent steps 108, 110, 112, and 114 of FIG. 7 .

FIG. 8C shows the system of FIG. 8B in a different orientation, asevidenced by axes of motion 12 & 14, such that incision 45 is seen to beprogressing through tissue 2 as electrode 702 is translated along axesof motion 12 (shown in this view as proceeding from left to right). Theactuation of electrode 702 may be in its final position, such as may bethe case when creating a flap incision.

FIG. 8D shows the system of FIGS. 8A-8C, wherein contact plate 804 andtherefore contact element 808 may have been moved along axis of motion14 to just rest atop the apex of corneal surface 842, as in FIG. 8A. Theimmediate figure now shows incision 45, which may form a surface for bed43 (not indicated). The surface shape of bed 43 thus created may benominally characterized as about that of the anterior corneal surface842. Alternately, the surface shape of the central region of bed 43 (notshown) thus created may characterized as the mean value of at leastportions of the surface shapes of the anterior corneal surface 842 andthe contact surface 806 (or contact element 808). Said mean maynominally be an arithmetic mean, a geometric mean, a harmonic mean, aweighted mean, or combinations thereof. The configuration of theimmediate figure may represent steps 116, 118, 120, and 122 of FIG. 7 .

FIG. 9 describes a method of similar to that of FIG. 7 , with additionalsteps 202 through 212; wherein step 116 may be made optional and allowthe electrode to incise during step 202. That is, alternately, steps 116& 118 may be eliminated if there is only low risk of collateral damagedue to tissue heating while the actuator changes direction and/or thestrain to an unpowered electrode may cause a failure of said electrodedue to the change in position of the contact plate. Step 202 involvespositioning a contact plate at a second position, which may be atranslation of the entire element, or a translation of at least aportion of the element. The translation of at least a portion of theelement may be utilized to create a non-planar contact plate surface toprovide a desired corneal deformation, as will described with regard toFIGS. 11A & 11B. Alternately, a contact plate may be interchanged atstep 202 to provide a desired corneal deformation. Said cornealdeformation may be intended to create a surface that defines at least aportion of a lenticule, such as bed 43, to achieve at least a portion ofa desired three-dimensional tissue resection profile. Said lenticule maybe subsequently removed to cause a refractive change to a cornea 843 ofan eye of a patient. Step 204 may be made optional, if step 202 isremoved, but may otherwise be similar to step 112. Step 206 involvestranslating an electrode in a second direction. Said second directionmay be nominally the opposite of said first direction. Step 208 involvesan electrode disengaging from tissue, such as may occur should thetranslation of step 206 bring the electrode outside of tissue 2. Step210 involves disengaging power to an electrode and may be similar tostep 116 of FIG. 7 . Step 212 involves disengaging the vacuum fixationand freeing the tissue and disengaging the eye being treated and may besimilar to step 118 of FIG. 7 . Step 122 involves deactivating thesystem and disengaging it from the eye similar to step 122 of FIG. 7 .

Although FIG. 9 shows a method of incising tissue in accordance withsome embodiments, one of ordinary skill in the art will recognize thatmany adaptations and variations can be made in accordance with thepresent disclosure. For example, the steps can be performed in anysuitable order, some of the steps repeated, some of the steps omitted,and combinations thereof.

In some embodiments, a processor as described herein is configured withinstructions to perform one or more of the steps of the method of FIG. 9.

FIGS. 10A through 10F are directed at a system similar to that of FIGS.8A through 8D, further configured such that the shape of contact surface806 may be configured as other than planar and is shown as convex andadditionally that a lenticule (e.g. lenticule 820) may be incised within(stromal) tissue 2 of cornea 843. The difference between a firstincision profile and a second incision profile may correspond to a shapeof a lenticule of tissue to be removed from the cornea to treat arefractive error of the eye.

FIG. 10A shows a system configured similarly to that of FIG. 8A, withthe addition of a curved surface 806 on contact plate 804. Likewise,contact element 806 is placed on curved contact surface 806 andnominally matches said curvature. The configuration of the immediatefigure may represent steps 102 through 108 of FIGS. 7 & 9 .

FIG. 10B shows the system of FIG. 10A, wherein contact plate 804 andtherefore contact element 808 may have been moved farther along axis ofmotion 14 to contact cornea 843 and tissue 2 therein. Unlike theconfiguration of FIGS. 8A through 8C, in the configuration of theimmediate figure the cornea is not necessarily applanated but caused tocompress to differentially to at least partially match the curvature (or“shape” in the case where a curvature alone cannot suffice to adequatelydescribe contact surface 806) of contact surface 806 in order to producean incision 46. The configuration of the immediate figure may representsteps 110 through 112 of FIGS. 7 and 9 .

FIG. 10C shows the system of the previous FIGS. 10X in a differentorientation, as evidenced by axes of motion 12 and 14, such thatincision 45 is seem to be progressing through tissue 2 as electrode 702is translated along axes of motion 12 (shown in this view as proceedingfrom left to right). The actuation of electrode 702 may be in its finalposition, such as may be the case when creating a flap incision.

FIG. 10D shows the system of the previous FIGS. 10X, wherein contactplate 804 has been translated anteriorly and incision 46 is nowindicated. Such incision 46 may form a surface for bed 44 (notindicated). The surface shape of bed 44 thus created may characterizedas the mean value of the surface shapes of the anterior corneal surface842 and the contact surface 806 (or contact element 808). Said mean maynominally be an arithmetic mean, a geometric mean, a harmonic mean, aweighted mean, or combinations thereof.

FIG. 10E shows the system of the previous FIGS. 10X, wherein a secondincision, incision 45, may now be created. The configuration of theimmediate figure may represent steps 202-206 of FIG. 9 . Alternately,incision 45 may be created by interchanging contact plate 804, orportions thereof, to provide a different surface shape for incision 45.A flat contact surface may be used for at least one the incisions.

FIG. 10F shows an eye treated with the system of the previous FIGS. 10X,wherein lenticule 820 has been incised within (stromal) tissue 2 ofcornea 843 and is bounded by surfaces created by incisions 45, 46.Incisions 45, 46 may comprise incisions 47 when the electrode is made toincise across the entire cornea rather than to create a pocket in thecornea. The configuration of the immediate figure may represent theoutcome of completing the remaining steps of FIG. 9 . The shapes ofsurfaces created via incisions 45, 46 may be chosen to affect arefractive correction to a cornea 843 of an eye of a patient. Saidrefractive correction may be defined, at least in part, by diagnosticmeasurements such as corneal aberrometry, ocular aberrometry, wavefrontaberrometry, corneal topography, and combinations thereof, where thenominal shape of the lenticule may be defined to optically balance (orcorrect) the measured aberrations, such as has been described in SekundoW. Small Incision Lenticule Extraction (SMILE) Principles, Techniques,Complication Management, and Future Concepts. 2015. Springer ChamHeidelberg; and the associated citations therein.

In some embodiments, for the cornea an approximate tissue profile fortissue to be removed may be expressed as:

T(x,y)˜=W(x,y)/(n−1) where T is the thickness in microns, W is thewavefront error in microns, n is the index of refraction of the corneaand x and y are the coordinate references corresponding to a plane, suchas a plane near the pupil or vertex of the cornea. The wavefront errorcan be expressed in many ways, such as with an elevation in microns, orwith individual Zernike coefficients for example.

Other approaches may be used to determine the thickness profile oftissue to be removed, for example with reference to the SMILE procedureas will be known to one of ordinary skill in the art.

FIGS. 11A & 11B are directed at a piecewise adjustable contact plate 804to deform the cornea in order to create a lenticule or other therapeuticincision. The adjustable contact plate 804 can be operatively coupled tothe controller and configured to shape the cornea to provide refractivecorrection, for example with reference to small incision lenticularextraction as described herein. FIG. 11A depicts piecewise adjustablecontact plate 804 comprised of sub-plates (or, equivalently, “elements”)8061, which together may be constitute a contact surface 806, that maybe housed within housing 8042 and mounted to base 8044. FIG. 11B depictsthe same contact plate 804 in a cross-sectional view in order to exposeactuators 8100 that are operatively coupled to sub-plates 8061 withinhousing 8042. In the instant embodiment, sub-plates 8061 may each beaffixed to an actuator 8100 to allow each subplate 8061 to beindividually actuated using additional actuators and associatedmonitoring and control subsystems, as shown and described in regard tothe system of FIG. 6 (said connections not indicated in the immediatefigure). By way of non-limiting example, sub-plates 8061 may be adheredto actuators 8100 using an epoxy or be soldered. Actuators 8100 may beselected from the group consisting of: piezoelectric actuators, motors,pneumatic actuators, fluidic actuators, and combinations thereof. Asshown in the exemplary embodiment, sub-elements 8062 may be constructedusing a material selected from the group consisting of: a glass, aceramic, a quartz, a silicon, a metal, a polymer, and combinationsthereof. Such sub-plates 8061 may be actuated along an axis of motion(e.g. axis of motion 14). Such sub-plates 8061 may be translated (or“displaced”) to form a piecewise contact surface 806 with a freeformprofile (or “shape” or “surface profile”) to create a contact surface806 with a discrete but arbitrarily addressable profile for use increating an incision 45 and/or an incision 46 to address opticalaberrations, including higher order aberrations, such as defocus, radialdistortion, sphere, spherical aberration, cylinder, cylindricalaberration, astigmatism, coma, and trefoil in prescribing a figure for alenticule to be removed from tissue 2 within a cornea 843. Suchsub-plates 8061 may be configured to be nominally rectangular, as shown,but need not be and other geometries are considered within the scope ofthe present disclosure. A contact element 808 (not shown) may be placedon the distal surface of contact plate 804 to provide a clean and/orsterile surface for contact with tissue 2 and may be configured as athin, conformal, peel-and-stick sterile barrier, which may also bedisposable, as was described elsewhere herein. Rather than utilizingstep 202 of FIG. 9 to reposition a contact plate 804, the immediateembodiment may allow for said step 202 to be modified to reconfigurecontact plate to a second configuration prior to creating anotherincision. The number of actuators 8100 may be determined by the spatialresolution requirements of a given prescription and/or the tolerance ofthe surface figure. By way of non-limiting examples, there may be anarray of 10 square cross-sectional shaped actuators 8100, or there maybe an array of 14 such actuators 8100, or there may be an array of 28such actuators 8100; which when configured to be square-packed withinthe extent of a nominally 12 mm diameter disk-shaped contact surfaceyield areas of ˜2.0 mm², ˜1.44 mm², and ˜0.80 mm² per actuator 8100,respectively. Alternately, a more regular array may be used, such as a4×4 square array to yield 16 actuators 8100. When said regular array of16 square cross-sectional shaped actuators 8100 is positioned concentricwith a nominally 12 mm disk-shaped contact surface, the area peractuator may be ˜9 mm², although the corners of the array may lieoutside of the 12 mm disk boundary. Similarly, a 10×10 square array mayyield an area per actuator of ˜1.44 mm²

Alternately, a customized contact plate 804 and/or contact surface 806may be fabricated to comprise a surface profile for use in creating anincision 45 and/or an incision 46 to address higher order aberrations inprescribing a figure for a lenticule to be removed from tissue 2 withina cornea 843. Alternately, such customized contact plate 804 and/orcontact surface 806 may be used individually in creating an incision 45and/or an incision 46. Alternately, a first customized contact plate 804and/or contact surface 806 may be used in creating an incision 45 and asecond customized contact plate 804 and/or contact surface 806 may beused in creating an incision 46, wherein the first and second customizedcontact plates 804 and/or contact surfaces 806 may be configured withdifferent surface profiles. Rather than utilizing step 202 of FIG. 9 toreposition a contact plate 804, the immediate embodiment may allow forsaid step 202 to be modified to substitute (or “interchange”) secondcontact plate prior to creating another incision. Means of fabricatingsuch customized contact plates 804 and/or contact surfaces 806 mayselected from the group consisting of: additive manufacturing, injectionmolding, machining, and combinations thereof.

In some embodiments, an optical prescription may comprise one or more ofsurface curvatures, optical power in diopters, material properties,indices of refraction, a wavefront measurement of the eye, orthicknesses. In some embodiments, a surface figure of an optic may bedefined as the perturbation of the optical surface from the opticalprescription. Low-frequency errors may be typically specified asirregularity, fringes of departure, or flatness and tend to transferlight from the center of the airy disk pattern into the first fewdiffraction rings. This effect may reduce the magnitude of thepoint-spread function without widening it, thus reducing the Strehlratio. Mid-frequency errors (or small-angle scatter) may be specifiedusing slope or (PSD) requirements and tend to widen or smear the pointspread function (PSF) and reduce contrast. Low-frequency andmid-frequency errors may both degrade the optical system performance.However, some figure imperfections may be omitted from a surface-figurespecification, as may be the case for optical power and occasionallyastigmatism. Optical systems may allow for individual optics to befocused, decentered, or tilted to compensate for specific aberrations.Surface accuracy and surface figure are terms often used to capture bothregions. To eliminate ambiguity, one may use microns as the unit valuein specifications.

FIGS. 12A & 12B are directed at the creation of a disc-shaped lenticule.FIG. 12A shows lenticule 820, which is comprised of anterior surface 451that may be created by incision 45 via step 114 of FIGS. 7 & 9 , andposterior surface 461 that may be created by incision 46 via step 118 ofFIGS. 7 & 9 . Hinge 1020 may be created via step 202 of FIG. 9 , thetranslation of contact plate to a second position between the creationof incisions 46 & 45. In the present figure the lenticule may appear tobe a flat disc as shown when it is spread upon a flat surface, as shown.FIG. 12B shows a cross-sectional view of the same lenticule 820 of FIG.12A. It the instant embodiment, a nominally planar contact plate may bepositioned to first position (or “depth” or “location”) to createincision 46 and then translated to a second, more anterior (or“proximal”), position in order to create incision 45. In theconfiguration of the instant embodiment, cross-sectional shape 1010 maybe nominally rectangular and faces 451 & 461 may be nominally parallel.Alternately, incision 45 more be created at a more posterior (or“distal”) position than that of incision 46 by appropriate translationof the contact plate.

FIG. 13 is directed at a plano-convex type lenticule, similar to that ofFIG. 12B, in accordance with embodiments of the present disclosure. Herelenticule 820 comprises anterior face 451 that may be created byincision 45 and posterior face 461 that may be created by incision 46.The contact plate, or elements of a contact plate comprised of aplurality of translatable elements, may be configured to produce anon-planar type of surface for face 451. The configuration of theinstant embodiment may be utilized to create a plano-convex typelenticule, as shown.

FIG. 14 is directed at a meniscus-shaped lenticule, similar to that ofFIG. 13 , in accordance with embodiments of the present disclosure. Herelenticule 820 comprises anterior face 451 that may be created byincision 45 and posterior face 461 that may be created by incision 46.The contact plate, or elements of a contact plate comprised of aplurality of translatable elements, may be configured to produce anon-planar type of surface for both faces 451 & 461. The configurationof the instant embodiment may be utilized to create a meniscus typelenticule, as shown.

FIG. 15 is directed at a hybrid type lenticule, similar to that of FIG.14 , in accordance with embodiments of the present disclosure. Herelenticule 820 comprises anterior face 451 that may be created byincision 45 and posterior face 461 that may be created by incision 46.The contact plate, or elements of a contact plate comprised of aplurality of translatable elements, may be configured to produce anon-planar type of surface for both faces 451 & 461. The configurationof the instant embodiment may be utilized to create a meniscus typelenticule, as shown.

FIGS. 16A & 16B are directed at histological images of incisions inporcine cornea created in accordance with embodiments of the presentdisclosure. FIG. 16A shows image 900, a traditional sagittalcross-sectional (H&E stained) histological microscopic image of aporcine cornea that was incised when fresh (≤2 days post-harvest, storedat ˜2° C.) and was subsequently fixed in a 4% paraformaldehyde solution.The incisional system was configured as follows: PRF˜1 MHz, V˜±250V,sinusoidal waveform, P_(rms)˜15 W; v_(t,max)˜400 mm·s⁻¹; constantacceleration ˜2000 mm·s⁻²; L˜10 mm, ˜99.99% pure tungsten wireelectrode; T˜290 mN; ˜35 μm contact plate (flat) posterior displacementbetween incisions 45 & 46, and a vacuum gauge pressure of ˜−500 mmHg forsuction element 810 as measured at vacuum sensor 854. Electrode assemblytranslation was accomplished using M-664.164 piezo-motor actuators from(PI, Karlsruhe, Germany). Target tissue 2 is corneal stromal tissue.Incision 45 was separated to reveal surfaces 451 and 452. Incision 46was left intact with lenticule 820 in place. Damage may be visible asthe darker bands along incisions 45 & 46 and may be on the order of ˜3μm in extent. FIG. 16B shows image 902, similar to that of FIG. 16A, butat a higher magnification and with the different spacing betweenincisions 45 & 46 by means of a ˜50 μm posterior contact platetranslation. Again, narrow damage zones are evident.

FIG. 17 is directed at plot 910, which displays an exemplary electrodevoltage versus time waveform 912 that comprises features in accordancewith embodiments of the present disclosure. Waveform 912 comprisesindividual cycles 914. Bursts 916 are comprised of pulses (cycles 914)and constrained by modulation envelope 918. Modulation envelope 918 maybe configured to be a combination of the relationships describedelsewhere herein, including pulsatile, duty cycle, and modulation (e.g.,ramping) relationships. While shown here for clarity at the level ofpulses and bursts, an entire incisional waveform may be similarlyconfigured.

FIG. 18 is directed at image 960, a 576 pixel×464 pixel frame, as may beobtained using a high-speed digital camera such as the AOS M-VIT 4000(AOS Technologies, Daettwil, Switzerland), when configured to operatewith an equivalent sensitivity of 6400 ISO, and a shutter speed (or“integration time”) of t_(sh)˜250 μs. In the instant figure, theplurality of vapor cavities 635 along image element 962 may show thestaccato disruption process, which may correspond to an electrodetranslation of about one diameter, as v_(t)*t_(sh)˜13 μm andPRF*t_(sh)→˜250 cycles of a ˜1 MHz waveform for an incisional systemconfigured similarly to that of FIGS. 6 through 10E: v_(t,max)˜400mm·s⁻¹; constant acceleration ˜2000 mm·s⁻²; ˜Ø13 μm, L˜10 mm, ˜≥99.99%pure tungsten wire electrode; T˜280 mN; and a vacuum gauge pressure of˜−640 mmHg for suction element 810 as measured using a vacuum sensor854, and nominally utilizing the waveform of FIG. 17 . A plurality ofvapor cavities 635 may be visible along image element 962 as anelectrode 702 (located at image element 962, but otherwise obscured inthe present figure) is actuated to translate along axis of motion 12 indirection 121 to create an incision within cornea 843. The plurality ofvapor cavities 635 may comprise regions where light is emitted inassociation with the formation of plasma, and the light may comprise awavelength that is a function of the plasma temperature and may liewithin a range from about 400 nm to about 750 nm.

In accordance with embodiments of the present disclosure the techniquedependency of scleral incisions may be reduced by semi-automating flapcreation using a plasma-induced cutting tool which limits tissue damageand providing predictable, accurate, and precise incisions in the scleraand/or cornea, including the sclero-corneal limbus. In accordance withembodiments of the present disclosure, pockets in the sclera and/orcornea, including the sclero-corneal limbus may be made rather than theflaps traditionally used. Further embodiments may provide for incisingother tissues, such as those listed in FIG. 1A. By way of non-limitingexample, a plasma-induced incision may be created in a CAPSULE toproduce a capsulorrhexis; in a LENS to produce lens fragments or tosimplify lens fragmentation and/or lens removal; in a RETINA to producea pocket or flap, in a TM to improve drainage and/or to lower IOP; andin an IRIS to produce an iridotomy.

A flap may be described as an incision yielding a “flap” of tissue thatmaybe lifted and pivot on a “hinge” to provide access to the tissuebeneath it. By way of nonlimiting example, cutting three sides of asquare to the 50% depth and razing a plane at that 50% depth beneath theedges of the square of a tissue may yield a half-thickness flap with thefourth uncut side of the square as its hinge. A flap may be amputated bycompleting the fourth side of the exemplary square incision.

A pocket maybe described as an incision that separates a first depth (orlayer) of tissue from a second depth (or layer) of tissue withoutnecessarily creating a flap. By way of a further nonlimiting example,cutting one side of a square to the 50% depth and razing a plane at that50% depth beneath the edges of the square of a tissue may yield ahalf-thickness pocket.

A semi-automated cutting tool may be used to yield an incision improvedover those of traditional sharp-edged instruments. A plasma-induced,semi-automated cutting tool may be used to yield an incision improvedover those of a semi-automated cutting tool configured for use withtraditional sharp-edged instruments.

A semi-automated cutting system with at least one degree of motion maybe used to create the 5×5 mm and 4×4 mm flaps instead of manuallycreating them. For example, a system comprising both 5 mm wide and 4 mmwide “blades” may be used to create the 5×5 mm and 4×4 mm flaps,respectively. An electrode may comprise a wire and/or a blade.

FIG. 19A shows flap 40 in tissue 2 as seen from above, and FIG. 19Bshows the same flap 40 as seen looking into cross-section A-A. Flap 40is constructed of incisions 42 and 44, which create bed 43 and form 3sides of a square (in the examples of FIGS. 19A-19D, although other suchshapes are also considered within the scope of the present disclosure).The flap may be lifted and hinge about the missing side of the square toexpose the tissue beneath. Bed 43 may be planar or curved. A flap may beamputated by completing the fourth side of the exemplary squareincision.

Similar to the configuration of FIGS. 19A & 19B, FIG. 19C shows pocket41 in tissue 2 as seen from above, and FIG. 19D shows the same pocket 41as seen looking into cross-section A-A. However, in this configuration,pocket 41 is comprised of incision 42, which creates bed 43, but lacksincisions 44. Again, bed 43 may be planar or curved, but this time willbe dependent upon the longitudinal shape (or “profile”) of the incisorin order to avoid creating incisions 44.

FIG. 20 is directed at a system in accordance with embodiments of thepresent disclosure configured to create a rectangular flap or pocket asmay be useful in canaloplasty for the reduction of TOP in the treatmentof glaucoma. Tissue 2 may be incised using electrode 4, which isconfigured in a U-shape of width 6 and length 8 and comprises bends 10in this exemplary embodiment. Electrode 4 may be connected to power RFdriver 18 via lead 20. Lead 22 may be connected to the patient creatingelectrode 24, which in turn may be a part of a return path. RF drivermay produce bipolar pulses. Electrode 4 may be enclosed within a sheath16, shown here as partially cut-away for clarity. Direction of motion 12may be used to provide a lateral extent to the incision and direction ofmotion 14 may be orthogonal to direction of motion 12 and perpendicularto the plane described by the width 6 of U-shape of electrode 4, such asmay be used to create a tissue flap and/or pocket. Alternately,direction of motion 14 maybe employed to create an incision nominallyperpendicular to a surface of tissue 2. Width 6 may be chosen to bebetween 1 mm and 10 mm, specifically 4 mm or 5 mm, as described above.Length 8 may be greater than width 6 and made to traverse tissue adistance less than length 8. For example, a 4 mm×4 mm flap may becreated by configuring width 6 to be 4 mm and length 8 to be greaterthan 4 mm but made to traverse 4 mm of tissue along direction of motion12.

FIG. 21 is directed at a system similar to that of FIG. 20 , as seenfrom the side and configured to create a flap; with the additions ofprobe body 26 to contain electrode 4, sheath 16, and actuator 50; aswell being oriented at angle 30 relative the surface of tissue 2.Actuator 50 may be operatively coupled to electrode 4 and move indirections of motion 12&14 such that electrode 4 is made to translatewithin tissue 2 along a motion profile described by moving first indirection 32; then direction 34; then direction 36, which is in oppositedirection from direction 34; then direction 38, which is in oppositedirection from direction 32. This configuration may then create a flap40 (not explicitly shown for purposes of clarity) by creating incision42, then incision 44 and bed 43. Actuator 50 may be powered, such as amotor or voice coil, by way of non-limiting examples. Alternately,actuator 50 may comprise a series of springs and ratchets or stop andtriggers to create the motion profile described. Elements electrode 4and/or sheath 6 and/or probe body 26 may be configured to be a subsystemthat engages with actuator 50 and RF driver 18 and to be disposed ofafter use. In an alternate embodiment, a flap may be amputated byaltering the motion profile as follows: by moving first in direction 32;then direction 34; then direction 38, which is in opposite directionfrom direction 32.

Alternately, the system of FIG. 21 may be configured such that actuator50 translates electrode 4 first in a direction that is nominally alongangle 30 then retract electrode 4 along a second direction that isnominally the opposite of the first direction in order to create apocket rather than a flap.

Alternately, a second electrode may also be used to create a second flapor pocket that of different size and/or shape than a first flap orpocket. For example, a 5 mm×5 mm flap may be first made first andsubsequently and 4 mm×4 mm flap may then be made. The exemplary 4 mm×4mm flap may further be an amputated flap.

FIGS. 22A-22C are directed at details of an electrode configured inaccordance with embodiments of the present disclosure, wherein electrode4 comprises regions 300, 302, and bends 10. Nominally, the surface areamay be kept constant along electrode 4. By way of non-limiting example,electrode 4 may comprise a solid wire of diameter between ˜50 μm and˜300 μm and be composed of a material selected from the group consistingof; tungsten, nitinol, steel, copper, stainless steel, beryllium-copperalloy, cupronickel alloy, and aluminum. Furthermore, in alternateembodiments, an electrode may be at least partially coated with anotherconducting material, such as gold. Region 302 may comprise the same basestructure as region 300 with the modification of being compressed in thedirection parallel to the plane of the image and elongated in anorthogonal direction. Such a configuration may maintain the surface areawhile providing increased strength in the aforementioned orthogonaldirection for improved reliability and strength while incising tissue byreducing dimension 303 to be less than dimension 301. Bends 10 may bemade from either the configuration of region 300, that of region 302, orbe made to transition between regions 300 & 302. Alternately, regions300 and 302 and/or bends 10 may be joined from disparate materials. In afurther alternate embodiment, electrode 4 may be constructed fromtungsten wire with a diameter of ˜250 μm, which has been compressedeverywhere except region 300 of length ˜3 mm and with a dimension 301that is nominally the same as the ˜250 μm native diameter of the wire,and to the native bends 10 located about the region 300 and made to haveradii of ˜0.5 mm to yield a width 6 of ˜4 mm while dimension 303 isconfigured to be formed by the aforementioned compression and to ˜400μm.

For purposes of clarity, electrode 4 has been shown thus far as beingU-shaped but it need not be. Rf driver 18 may provide an alternatingcurrent to electrode 4. Such an alternating current may be, by way ofnon-limiting examples; a sinewave, a square wave, a sawtooth wave, atriangle wave, or a combination thereof. The signal provided by rfdriver 18 may be configured to have a base (or “carrier”) frequencybetween ˜10 kHz and ˜10 MHz and it may be further modulated to comprisebursts of pulses at frequency of between ˜100 Hz and ˜3 MHz to create aduty cycle. The duty cycle may be between ˜0.01% and ˜100%. In alternateembodiments, the duty cycle may be between ˜60% and ˜80%. Thepeak-to-peak voltage provided by rf driver 18 may be between ˜500V and˜2000V. In alternate embodiments, the peak-to-peak voltage provided byrf driver 18 may be between ˜400V and ˜800V. In one embodiment thesignal of rf driver 18 may be configured to have a peak-to-peak bipolarvoltage of ˜800V (comprising both ˜+400V and ˜−400V amplitudes) with acarrier frequency of ˜1MHz and a modulation frequency of ˜10 kHz, suchas may be useful when electrode 4 is comprised of a ˜Ø100 μm diametertungsten wire in region 300.

FIG. 23 is directed at system 400, which is configured in accordancewith embodiments of the present disclosure. In addition to the elementsrelated to previous figures, system 400 further comprises controller 60,power supply 70, user interface 80, and coupler 52. Connection 62connects controller 60 with RF driver 18 and is at least aunidirectional connection. Connection 62 may also be a bidirectionalconnection wherein controller 60 is able to sense and/or respond to atleast a signal from rf driver 18. Such a signal may be a safety signalrelated to a sensed voltage or current. In a further alternateembodiment, rf driver 18 may provide feedback to controller 60 or usesuch feedback internally and may share such feedback as signals withcontroller 60. Such feedback may be, for example, EMF or currentfeedback and may be useful in determining when electrode 4 contactstissue and/or the status of the plasma. Such status may be, for example,whether or not the plasma in the glow discharge regime or not. Likewise,connection 65 connects controller 60 with actuator 50 and is at least aunidirectional connection. Actuator 50 may be comprised of at least oneelectrical motor and may further comprise a positional encoder.Connection 65 may alternately be a bidirectional connection whereinsignals are shared between controller 60 and actuator 50, such asposition, velocity, acceleration, out of bounds errors, etc. In afurther alternate embodiment, actuator 50 may provide feedback tocontroller 60 or use such feedback internally and may share suchfeedback as signals with controller 60. Such feedback may be, forexample, force feedback and may be useful in determining when electrode4 contacts tissue or when it imparts excessive force on the tissue to beincised. Likewise, connection 67 connects controller 60 with powersupply 70 and is at least a unidirectional connection. In a furtheralternate embodiment, power supply 70 may provide feedback to controller60 or use such feedback internally and may share such feedback assignals with controller 60. Such feedback may be, for example, an errorsignal. Such error signals may be temperature errors, input voltageerrors, output voltage errors, input current errors, output currenterrors, etc. Likewise, connection 68 connects controller 60 with userinterface 80 and is at least a unidirectional connection. In a furtheralternate embodiment, interface 80 may provide feedback to controller 60or use such feedback internally and may share such feedback as signalswith controller 60. For example, user interface 80 may be a graphicaluser interface or a button used to signal actuator 50 to move electrode4 and incise tissue. This exemplary embodiment of system 400 alsoincludes coupler 52, which may couple electrode 4 to actuator 50 suchthat electrode 4 may be moved, as described with respect to earlierfigures. Coupler 52 may be constructed from an electrically insulatingmaterial and be configured to electrically isolate electrode 4 from atleast one other element of system 400. Coupler 52, and/or sheath 16, aswell as electrode 4 may be joined into a subsystem that may be disposedof after use. Although not shown, an alternate embodiment is aconfiguration for coupler 52 that may be made to connect both sides ofthe (exemplary) U-shaped electrode 4 to actuator 50. Electrode 4 may betranslated by actuator 50 at a rate of ˜200 mm·s⁻¹.

The symbol “˜” is used herein as equivalent to “about”. For example, astatement such as “˜100 ms” is equivalent to a statement of “about 100ms” and a statement such as “v_(t)=˜5 mm·s⁻¹” is equivalent to astatement of “v_(t) is about 5 mm·s⁻¹.”

The symbol “Ø” is used herein to indicate the following value is adiameter. For example, a statement such as “Ø10 μm” is equivalent to astatement of “a diameter of 10 μm.” Furthermore, a statement such as“˜Ø12 μm” is equivalent to a statement of “a diameter of about 12 μm.”

The symbol “∝” is used herein to indicate proportionality. For example,a statement such as “∝r⁻²” is equivalent to the statement “proportionalto r⁻².”

Dot notation is used herein to represent compound units for the sake ofclarity and brevity. For example, the statement k=˜40 N·m⁻¹ isequivalent to the statement “k=˜40 N per meter.”

As used herein “mN” refers to “milli Newtons”, which is 10⁻³ Newtons.

As described herein, the computing devices and systems described and/orillustrated herein broadly represent any type or form of computingdevice or system capable of executing computer-readable instructions,such as those contained within the modules described herein. In theirmost basic configuration, these computing device(s) may each comprise atleast one memory device and at least one physical processor.

The term “memory” or “memory device,” as used herein, generallyrepresents any type or form of volatile or non-volatile storage deviceor medium capable of storing data and/or computer-readable instructions.In one example, a memory device may store, load, and/or maintain one ormore of the modules described herein. Examples of memory devicescomprise, without limitation, Random Access Memory (RAM), Read OnlyMemory (ROM), flash memory, Hard Disk Drives (HDDs), Solid-State Drives(SSDs), optical disk drives, caches, variations or combinations of oneor more of the same, or any other suitable storage memory.

In addition, the term “processor” or “physical processor,” as usedherein, generally refers to any type or form of hardware-implementedprocessing unit capable of interpreting and/or executingcomputer-readable instructions. In one example, a physical processor mayaccess and/or modify one or more modules stored in the above-describedmemory device. Examples of physical processors comprise, withoutlimitation, microprocessors, microcontrollers, Central Processing Units(CPUs), Field-Programmable Gate Arrays (FPGAs) that implement softcoreprocessors, Application-Specific Integrated Circuits (ASICs), portionsof one or more of the same, variations or combinations of one or more ofthe same, or any other suitable physical processor. The processor maycomprise a distributed processor system, e.g. running parallelprocessors, or a remote processor such as a server, and combinationsthereof.

Although illustrated as separate elements, the method steps describedand/or illustrated herein may represent portions of a singleapplication. In addition, in some embodiments one or more of these stepsmay represent or correspond to one or more software applications orprograms that, when executed by a computing device, may cause thecomputing device to perform one or more tasks, such as the method step.

In addition, one or more of the devices described herein may transformdata, physical devices, and/or representations of physical devices fromone form to another. Additionally or alternatively, one or more of themodules recited herein may transform a processor, volatile memory,non-volatile memory, and/or any other portion of a physical computingdevice from one form of computing device to another form of computingdevice by executing on the computing device, storing data on thecomputing device, and/or otherwise interacting with the computingdevice.

The term “computer-readable medium,” as used herein, generally refers toany form of device, carrier, or medium capable of storing or carryingcomputer-readable instructions. Examples of computer-readable mediacomprise, without limitation, transmission-type media, such as carrierwaves, and non-transitory-type media, such as magnetic-storage media(e.g., hard disk drives, tape drives, and floppy disks), optical-storagemedia (e.g., Compact Disks (CDs), Digital Video Disks (DVDs), andBLU-RAY disks), electronic-storage media (e.g., solid-state drives andflash media), and other distribution systems.

A person of ordinary skill in the art will recognize that any process ormethod disclosed herein can be modified in many ways. The processparameters and sequence of the steps described and/or illustrated hereinare given by way of example only and can be varied as desired. Forexample, while the steps illustrated and/or described herein may beshown or discussed in a particular order, these steps do not necessarilyneed to be performed in the order illustrated or discussed.

The various exemplary methods described and/or illustrated herein mayalso omit one or more of the steps described or illustrated herein orcomprise additional steps in addition to those disclosed. Further, astep of any method as disclosed herein can be combined with any one ormore steps of any other method as disclosed herein.

The processor as described herein can be configured to perform one ormore steps of any method disclosed herein. Alternatively or incombination, the processor can be configured to combine one or moresteps of one or more methods as disclosed herein.

Unless otherwise noted, the terms “connected to” and “coupled to” (andtheir derivatives), as used in the specification and claims, are to beconstrued as permitting both direct and indirect (i.e., via otherelements or components) connection.

Unless otherwise noted, the terms “operatively connected to” and“operatively coupled to” (and their derivatives), as used in thespecification and claims, are to be construed as permitting both directand indirect (i.e., via other elements or components) connection toperform a function.

In addition, the terms “a” or “an,” as used in the specification andclaims, are to be construed as meaning “at least one of” Finally, forease of use, the terms “including” and “having” (and their derivatives),as used in the specification and claims, are interchangeable with andshall have the same meaning as the word “comprising.

The processor as disclosed herein can be configured with instructions toperform any one or more steps of any method as disclosed herein.

It will be understood that although the terms “first,” “second,”“third”, etc. may be used herein to describe various layers, elements,components, regions or sections without referring to any particularorder or sequence of events. These terms are merely used to distinguishone layer, element, component, region or section from another layer,element, component, region or section. A first layer, element,component, region or section as described herein could be referred to asa second layer, element, component, region or section without departingfrom the teachings of the present disclosure.

As used herein, the term “or” is used inclusively to refer items in thealternative and in combination.

As used herein, characters such as numerals refer to like elements.

The present disclosure includes the following numbered clauses.

Clause 1. A system for incising tissue with a plasma, comprising: anelongate electrode, the elongate electrode configured to flex andgenerate the plasma to incise the tissue; an electrical energy sourceoperatively coupled to the elongate electrode and configured to provideelectrical energy to the electrode to generate the plasma; and atensioning element operatively coupled to the elongate electrode, thetensioning element configured to provide tension to the elongateelectrode to allow the elongate electrode to flex in response to theelongate electrode engaging the tissue and generating the plasma.

Clause 2. The system of clause 1, further comprising a plurality of armsoperatively coupled to the electrode and the tensioning element.

Clause 3. The system of clause 2, wherein the electrode is unsupportedbetween the two arms.

Clause 4. The system of clause 2, wherein the electrode is configured tovibrate transversely to an elongate axis of the electrode.

Clause 5. The system of clause 2, further comprising a support structureoperatively coupled to the plurality of arms and the tensioning element,wherein the support structure is configured to advance the plurality ofarms and the tensioning element in order to advance the elongateelectrode into tissue to incise the tissue.

Clause 6. The system of clause 5 wherein an incisional portion of theelongate electrode is suspended between the plurality of arms withtension from the tensioning element and wherein a gap extends betweenthe plurality of arms.

Clause 7. The system of clause 6 wherein the gap extends between theincisional portion of the elongate electrode, the plurality of arms andthe support structure.

Clause 8. The system of clause 6 wherein the gap is sized to receiveincised tissue along an incision formed with the elongate electrode.

Clause 9. The system of clause 5 wherein the support structure isoperatively coupled to one or more actuators to move the elongateelectrode in one or more directions.

Clause 10. The system of clause 9 wherein the one or more actuators isconfigured to move the electrode with a variable velocity.

Clause 11. The system of clause 1, wherein the tensioning element isselected from the group consisting of a spring, a coil spring, a leafspring, a torsion spring, a mesh, a hinge, and a living hinge.

Clause 12. The system of clause 1, wherein the elongate electrodecomprises a first portion of an elongate filament and wherein thetensioning element comprises a second portion of the elongate filamentshaped to tension the elongate electrode.

Clause 13. The system of clause 1, further comprising an electrodeassembly, the electrode assembly comprising a support structureoperatively coupled to a plurality of arms and the tensioning element,wherein the electrode assembly is configured to advance the electrodeinto tissue to incise the tissue.

Clause 14. The system of clause 1, wherein the electrode is configuredto sequentially contact a plurality of locations of the tissue togenerate the incision.

Clause 15. The system of clause 14, wherein the plurality of locationscomprises a plurality of discontiguous locations.

Clause 16. The system of clause 15, wherein the electrode is configuredto vaporize tissue in contact with the electrode at each of theplurality of discontiguous locations.

Clause 17. The system of clause 1, wherein the electrode is configuredto generate a plurality of flashes of light energy at a plurality oflocations while the electrode incises the tissue.

Clause 18. The system of clause 17, wherein the plurality of flashes oflight energy comprise visible light energy comprising a wavelengthwithin a range from about 400 nm to about 750 nm.

Clause 19. The system of clause 17, wherein each of the plurality offlashes of light energy comprises maximum distance across of no morethan about 1 mm.

Clause 20. The system of clause 17, wherein the plurality of flashes isgenerated within a time interval of no more than about 250 μs andoptionally no more than about 25 μs.

Clause 21. The system of clause 17, wherein the plurality of flashes isgenerated with an electrode movement distance of no more than about 100μm and optionally no more than about 10 μm.

Clause 22. The system of clause 17, wherein the plurality of flashes oflight is distributed at a plurality of non-overlapping regions.

Clause 23. The system of clause 22, wherein the plurality ofnon-overlapping regions is located along the elongate electrode.

Clause 24. The system of clause 17, wherein the plurality of flashes oflight are generated at a first rate with a first velocity of theelectrode and a second rate with a second velocity of the electrode,wherein the first rate is greater than the second rate when the firstvelocity is less than the second velocity and wherein the first rate isless than the second rate when the first velocity is greater than thesecond velocity.

Clause 25. The system of clause 24, wherein the plurality of flashes oflight is generated at a substantially constant rate to within about 25%and wherein one or more of a pulse rate or a burst rate of a waveform tothe elongate electrode is varied in response to the a varying velocityof the electrode to maintain the substantially constant rate.

Clause 26. The system of clause 1, wherein the elongate electrodecomprises a filament and wherein the filament comprises one or more of awire or a thread.

Clause 27. The system of clause 1, wherein the elongate electrodecomprises a wire.

Clause 28. The system of clause 27, wherein a diameter of the wire iswithin a range from 5 μm to 200 μm, optionally from about 5 μm to about100 μm, optionally from about 5 μm to about 50 μm, optionally from about5 μm to about 25 μm, or optionally from about 5 μm to about 20 μm.

Clause 29. The system of clause 1, wherein the elongate electrodecomprises a cross-sectional distance and wherein the cross-sectionaldistance comprises no more than about 25 μm.

Clause 30. The system of clause 1, wherein the elongate electrodeoperatively coupled to the tensioning element comprises a mechanicalresonance frequency within a range from about 1 kHz to about 100 kHz andoptionally within a range from about 2 kHz to about 50 kHz.

Clause 31. The system of clause 1, wherein the tensioning element isconfigured to tension the elongate electrode with a force within a rangefrom about 20 mN to about 2N and optionally within a range from about 50mN to about 1N and further optionally within a range from about 100 mNto about 500 mN.

Clause 32. The system of clause 1, wherein the elongate electrodecomprises a mass per unit length within a range from about 0.2 μg·mm-1to about 3 μg·mm-1.

Clause 33. The system of clause 1, wherein elongate electrode comprisesa material selected from the group consisting of tungsten, nitinol,steel, copper, brass, titanium, stainless steel, beryllium-copper alloy,cupronickel alloy, palladium, platinum, platinum-iridium, silver, andaluminum.

Clause 34. The system of clause 1, wherein elongate electrode comprisesan axis along an elongate direction of the electrode and wherein theelectrode is configured to incise tissue with movement in a directiontransverse to the axis.

Clause 35. The system of clause 1, wherein elongate electrode isconfigured to incise tissue in a direction transverse to an elongatedirection of the electrode at a velocity greater than about 1 m·s-1.

Clause 36. The system of clause 1, wherein elongate electrode isconfigured to incise tissue in a direction transverse to an elongatedirection of the electrode at a velocity within a range from about 0.5cm·s-1 to about 10 m·s-1 and optionally within a range from about 1cm·s-1 to about 5 m·s-1.

Clause 37. The system of clause 1, wherein the electrode is configuredto incise an area of tissue at a rate within a range from about 5mm2·s-1 to about 50,000 mm2·s-1 and optionally within a range from about500 mm2·s-1 to about 25,000 mm2·s-1.

Clause 38. The system of clause 1, wherein the electrical energy sourceis configured to deliver a waveform, wherein the waveform comprises oneor more of a pulsatile waveform, a sinusoidal waveform, a squarewaveform, a sawtooth waveform, a triangular waveform, a fixed frequencywaveform, a variable frequency waveform, or a gated waveform.

Clause 39. The system of clause 38, wherein the waveform comprises thesinusoidal waveform and wherein the sinusoidal waveform comprises afrequency within a range from about 0.5 MHz to about 2 MHz.

Clause 40. The system of clause 38, wherein the waveform comprises acombination of the sinusoidal waveform and the gated waveform andwherein the sinusoidal waveform comprises a frequency within a rangefrom about 0.5 MHz to about 2 MHz and wherein the gated waveformcomprises a gate frequency within a range from about 20 kHz to about 80kHz and a duty cycle within a range from about 35% to about 100%.

Clause 41. The system of clause 1, further comprising a controlleroperatively coupled to the electrical energy source.

Clause 42. The system of clause 41, wherein the controller is configuredto control parameters of the electrical energy source by modulating thewaveform using a parameter selected from the group consisting of avoltage, a current, a carrier frequency, a modulation frequency, a dutycycle, a power setpoint, a power limit, an energy per pulse setpoint, anenergy per pulse limit, and a modulation envelope.

Clause 43. The system of clause 42, wherein the waveform comprises apulsatile voltage waveform comprising pulses and a substantiallyconstant frequency within a range from about 10 kHz to about 10 MHz andoptionally within a range from about 0.5 MHz to about 2 MHz.

Clause 44. The system of clause 43, wherein the waveform provides anenergy per pulse of within a range from about 0.5 μJ to about 50 μJ andoptionally within a range from about 1 μJ to about 10 μJ.

Clause 45. The system of clause 44, wherein the controller is configuredto modulate the substantially constant frequency waveform to producebursts.

Clause 46. The system of clause 45, wherein a frequency of the bursts iswithin a range from about 100 Hz and about 3 MHz and optionally within arange from about 1 kHz to about 100 kHz.

Clause 47. The system of clause 46, wherein the waveform from theelectrical energy source is configured to supply an average power withina range from about 1 W to about 25 W.

Clause 48. The system of clause 5, further comprising a translationelement operatively coupled to the support structure and configured todirect the support structure along an axis of motion transverse to anelongate axis of the electrode.

Clause 49. The system of clause 48, wherein the translation element isselected from the group consisting of a translation stage, a linearstage, a rotary stage, a rail, a rod, a cylindrical sleeve, a screw, aroller screw, a travelling nut, a rack, a pinion, a belt, a chain, alinear motion bearing, a rotary motion bearing, a cam, a flexure, and adovetail.

Clause 50. The system of clause 49, comprising an actuator operativelycoupled to the translation element to move the support structure alongan axis of motion.

Clause 51. The system of clause 50, wherein the translation element ismanually actuated.

Clause 52. The system of clause 50, wherein the actuator is selectedfrom the group consisting of a motor, a rotary motor, a squiggle motor,a linear motor, a solenoid, a rotary solenoid, a linear solenoid, avoice coil, a spring, a moving coil, a piezoelectric actuator, apneumatic actuator, a hydraulic actuator, and a fluidic actuator.

Clause 53. The system of clause 5, wherein a portion of the supportstructure comprises a material selected from the group consisting oftungsten, nitinol, steel, copper, brass, titanium, stainless steel,beryllium-copper alloy, cupronickel alloy, palladium, platinum,platinum-iridium, silver, aluminum, polyimide, PTFE, polyethylene,polypropylene, polycarbonate, poly(methyl methacrylate), acrylonitrilebutadiene styrene, polyamide, polylactide, polyoxymethylene, polyetherether ketone, polyvinyl chloride, polylactic acid, glass, and ceramic.

Clause 54. The system of clause 48, wherein the translation elementcomprises a first translation element having a first axis of motion anda second translation element having a second axis of motion differentfrom the first axis of motion.

Clause 55. The system of clause 54, wherein the first and secondtranslation elements are each selected from the group consisting of atranslation stage, a linear stage, a rotary stage, a rail, a rod, acylindrical sleeve, a screw, a roller screw, a travelling nut, a rack, apinion, a belt, a chain, a linear motion bearing, a rotary motionbearing, a cam, a flexure, and a dovetail.

Clause 56. The system of clause 55, further comprising a contact plateoperatively coupled to the second translation element to engage aportion of the tissue to shape the tissue prior to incising the tissuewith the electrode.

Clause 57. The system of clause 1, further comprising a contact plateoperatively coupled to the elongate electrode, the contact plateconfigured to engage a portion of a cornea to shape the cornea prior toincising the cornea with the electrode.

Clause 58. The system of clause 57, wherein the contact plate comprise afirst contact plate have a first surface profile and a second contactplate having a second surface profile, a difference between the firstsurface profile and the second surface profile corresponding to arefractive correction of an eye to correct the refractive error of theeye.

Clause 59. The system of clause 57, wherein the contact plate comprisesa free-form optical surface shaped to correct wavefront aberrations aneye.

Clause 60. The system of clause 57, wherein the contact plate comprisesa plurality of independently adjustable actuators to shape the cornea.

Clause 61. The system of clause 60, wherein the contact plate comprisesa plurality of plates operatively coupled to the independentlyadjustable actuators to shape the cornea.

Clause 62. The system of clause 61, wherein each of the plurality ofplates is configured to be driven to a first position and a secondposition at each of a plurality of locations, a difference between thefirst position and the second position corresponding to a shape profileof tissue to be resected from the cornea to ameliorate refractive errorof the eye.

Clause 63. The system of clause 62, wherein the plurality of locationscomprises a plurality of two-dimensional locations and the shape profilecomprises a three-dimensional tissue resection profile.

Clause 64. The system of clause 60, wherein the plurality of actuatorscomprises at least 10 actuators and optionally wherein the plurality ofactuators comprises at least 16 actuators and optionally wherein theplurality of actuators comprises at least 42 actuators and optionallywherein the plurality of actuators comprises at least 100 actuators.

Clause 65. The system of clause 60, wherein the contact plate comprisesa deformable membrane operatively coupled to the plurality ofindependently adjustable actuators.

Clause 66. The system of clause 60, wherein the contact plate comprisesa first configuration for a first incision with the electrode along afirst incision profile and a second configuration for a second incisionwith the electrode along a second incision profile and wherein adifference between the first incision profile and the second incisionprofile corresponds to a shape of a lenticule of tissue to be removedfrom the cornea to treat a refractive error of the eye.

Clause 67. The system of clause 57, wherein the contact plate isconfigured to correct one or more of sphere, cylinder, coma, sphericalaberration, or trefoil of an eye.

Clause 68. The system of clause 57, further comprising a suction elementto engage tissue retain the tissue in contact with the secondtranslation element in a substantially fixed position while the firsttranslation element moves the electrode to incise the tissue.

Clause 69. The system of clause 57, further comprising sterile barrierfor placement on the contact plate to maintain sterility of the eye.

Clause 70. The system of clause 69, wherein the sterile barriercomprises a thin conformal barrier to conform to the shape of thecontact plate with the sterile barrier between the eye and the contactplate.

Clause 71. The system of clause 69, wherein the sterile barriercomprises a peel-and-stick sterile barrier.

Clause 72. The system of clause 57, wherein: a length of the elongateelectrode is within a range from about 6 mm to about 12 mm; the tissuecomprises corneal tissue; the electrode comprises a wire having adiameter within a range from about 5 μm to about 20 μm; and wherein thetensioning element is configured to provide a tension to the electrodewithin a range from about 100 mN to about 500 mN.

Clause 73. The system of clause 1, further comprising: a processoroperatively coupled to the elongate electrode, the processor configuredwith instructions to advance the electrode distally and draw theelectrode proximally.

Clause 74. The system of clause 73, wherein: the elongate electrode issized for insertion into the tissue; the processor is configured withinstructions to incise the tissue with the electrode to define a volumeof incised tissue; and wherein the volume comprises a shape profile.

Clause 75. The system of clause 74, wherein the processor is configuredwith instructions to move the electrode with a first movement to definea first surface on a first side of the volume of tissue and move with asecond movement to define a second surface on a second side of thevolume of tissue.

Clause 76. The system of clause 74, wherein the processor is configuredwith instructions to advance the electrode distally to define a firstsurface on a first side of the volume of tissue and to draw theelectrode proximally to define a second surface on a second side of thevolume of tissue.

Clause 77. The system of clause 76, wherein a gap extends between theelongate electrode and the support structure and wherein the gap issized to receive tissue and wherein tissue extending into the gap isincised when the electrode is drawn proximally.

Clause 78. The system of clause 74, the contact plate comprises a firstconfiguration to define a first surface on a first side of the volume oftissue and a second configuration to define a second surface on a secondside of the volume of tissue.

Clause 79. The system of clause 74, wherein a first contact platecomprises a first shape profile to define a first surface on a firstside of the volume of tissue and a second shape profile to define asecond surface on a second side of the volume of tissue.

Clause 80. The system of clause 74, wherein the shape profile comprisesa thickness profile.

Clause 81. A system to treat a refractive error of an eye, the systemcomprising: an elongate electrode to incise corneal tissue; anelectrical energy source operatively coupled to the elongate electrodeand configured to provide electrical energy to the electrode; a contactplate configured to engage a portion of a cornea to shape the corneaprior to incising the cornea with the electrode; and a support structureoperatively coupled to the elongate electrode and the plate, the supportconfigured to move the electrode relative to the plate and incise thecorneal tissue with the electrode.

Clause 82. The system of clause 81, further comprising a translationelement operatively coupled to the support structure and the elongateelectrode to incise the corneal tissue with translation of theelectrode.

Clause 83. The system of clause 81, wherein the contact plate comprise afirst contact plate have a first surface profile and a second contactplate having a second surface profile, a difference between the firstsurface profile and the second surface profile corresponding to arefractive correction of an eye to correct the refractive error of theeye.

Clause 84. The system of clause 81, wherein the contact plate comprisesa free-form optical surface shaped to correct wavefront aberrations aneye.

Clause 85. The system of clause 81, wherein the contact plate comprisesa plurality of independently adjustable actuators to shape the cornea.

Clause 86. The system of clause 85, wherein the contact plate comprisesa plurality of plates operatively coupled to the independentlyadjustable actuators to shape the cornea.

Clause 87. The system of clause 86, wherein each of the plurality ofplates is configured to be driven to a first position and a secondposition at each of a plurality of locations, a difference between thefirst position and the second position corresponding to a shape profileof tissue to be resected from the cornea to ameliorate refractive errorof the eye.

Clause 88. The system of clause 87, wherein the plurality of locationscomprises a plurality of two-dimensional locations and the shape profilecomprises a three-dimensional tissue resection profile.

Clause 89. The system of clause 85, wherein the plurality of actuatorscomprises at least 10 actuators and optionally wherein the plurality ofactuators comprises at least 16 actuators and optionally wherein theplurality of actuators comprises at least 42 actuators and optionallywherein the plurality of actuators comprises at least 100 actuators.

Clause 90. The system of clause 85, wherein the contact plate comprisesa deformable membrane operatively coupled to the plurality ofindependently adjustable actuators.

Clause 91. The system of clause 85, wherein the contact plate comprisesa first configuration for a first incision with the electrode along afirst incision profile and a second configuration for a second incisionwith the electrode along a second incision profile and wherein adifference between the first incision profile and the second incisionprofile corresponds to a shape of a lenticule of tissue to be removedfrom the cornea to treat a refractive error of the eye.

Clause 92. The system of clause 81, wherein the contact plate isconfigured to correct one or more of sphere, cylinder, coma, sphericalaberration, or trefoil of an eye.

Clause 93. The system of clause 81, further comprising a suction elementto engage tissue retain the tissue in contact with the secondtranslation element in a substantially fixed position while the firsttranslation element moves the electrode to incise the tissue.

Clause 94. The system of clause 81, further comprising sterile barrierfor placement on the contact plate to maintain sterility of the eye.

Clause 95. The system of clause 94, wherein the sterile barriercomprises a thin conformal barrier to conform to the shape of thecontact plate with the sterile barrier between the eye and the contactplate.

Clause 96. The system of clause 94, wherein the sterile barriercomprises a peel-and-stick sterile barrier.

Clause 97. The system of clause 81, wherein: a length of the elongateelectrode is within a range from 6 mm to 12 mm; the electrode comprisesa wire having a diameter within a range from 5 μm to 20 μm; and whereinthe tensioning element is configured to provide a tension to theelectrode within a range from 100 mN to 500 mN.

Clause 98. The system of clause 81, further comprising: a processoroperatively coupled to the elongate electrode, the processor configuredwith instructions to advance the electrode distally and draw theelectrode proximally.

Clause 99. The system of clause 98, wherein: the elongate electrode issized for insertion into a cornea of the eye to treat a refractive errorof the eye; the processor is configured with instructions to incise thecornea with the electrode to define a lenticle of corneal tissue withina pocket; and wherein the lenticle comprises a shape profilecorresponding to treatment of the refractive error.

Clause 100. The system of clause 99, wherein the processor is configuredwith instructions to move the electrode with a first movement to definea first surface on a first side of the lenticle and moved with a secondmovement to define a second surface on a second side of the lenticle.

Clause 101. The system of clause 99, wherein the processor is configuredwith instructions to advance the electrode distally to define a firstsurface on a first side of the lenticle and to draw the electrodeproximally to define a second surface on a second side of the lenticle.

Clause 102. The system of clause 101, wherein a gap extends between theelongate electrode and the support structure and wherein the gap issized to receive tissue and wherein tissue extending into the gap isincised when the electrode is drawn proximally.

Clause 103. The system of clause 99, the contact plate comprises a firstconfiguration to define a first surface on a first side of the lenticuleand a second configuration to define a second surface on a second sideof the lenticule.

Clause 104. The system of clause 99, wherein a first contact platecomprises a first shape profile to define a first surface on a firstside of the lenticule and a second shape profile to define a secondsurface on a second side of the lenticule.

Clause 105. The system of clause 99, wherein the shape profile comprisesa thickness profile.

Clause 106. A method for incising tissue with a plasma, comprising:incising tissue with an elongate electrode, the elongate electrodeconfigured to flex and generate the plasma to incise the tissue; whereinan electrical energy source is operatively coupled to the elongateelectrode and provides electrical energy to the electrode to generatethe plasma; and wherein a tensioning element is operatively coupled tothe elongate electrode and provides tension to the elongate electrode toallow the elongate electrode to flex in response to the elongateelectrode engaging the tissue and generating the plasma.

Clause 107. The method of clause 106, wherein a plurality of arms isoperatively coupled to the electrode and the tensioning element.

Clause 108. The method of clause 107, wherein the electrode isunsupported between the two arms.

Clause 109. The method of clause 107, wherein the electrode isconfigured to vibrate transversely to an elongate axis of the electrode.

Clause110. The method of clause 107, wherein a support structure isoperatively coupled to the plurality of arms and the tensioning element,wherein the support structure advances the plurality of arms, thetensioning element, and the elongate electrode to incise the tissue.

Clause 111. The method of clause 110, wherein an incisional portion ofthe elongate electrode is suspended between the plurality of arms withtension from the tensioning element and wherein a gap extends betweenthe plurality of arms.

Clause 112. The method of clause 111, wherein the gap extends betweenthe incisional portion of the elongate electrode, the plurality of armsand the support structure.

Clause 113. The method of clause 111, wherein the gap is sized toreceive incised tissue along an incision formed with the elongateelectrode.

Clause 114. The method of clause 110, wherein the support structure isoperatively coupled to one or more actuators to move the elongateelectrode in one or more directions.

Clause 115. The method of clause 114, wherein the one or more actuatorsmoves the electrode with a variable velocity.

Clause 116. The method of clause 106, wherein the tensioning element isselected from the group consisting of a spring, a coil spring, a leafspring, a torsion spring, a mesh, a hinge, and a living hinge.

Clause 117. The method of clause 106, wherein the elongate electrodecomprises a first portion of an elongate filament and wherein thetensioning element comprises a second portion of the elongate filamentshaped to tension the elongate electrode.

Clause 118. The method of clause 106, wherein an electrode assemblycomprising a support structure is operatively coupled to a plurality ofarms and the tensioning element, wherein the electrode assembly advancesthe electrode into tissue to incise the tissue.

Clause 119. The method of clause 106, wherein the electrode sequentiallycontacts a plurality of locations of the tissue to generate theincision.

Clause 120. The method of clause 119, wherein the plurality of locationscomprises a plurality of discontiguous locations.

Clause 121. The method of clause 120, wherein the electrode vaporizestissue in contact with the electrode at each of the plurality ofdiscontiguous locations.

Clause 122. The method of clause 106, wherein the electrode generates aplurality of flashes of light energy at a plurality of locations whilethe electrode incises the tissue.

Clause 123. The method of clause 122, wherein the plurality of flashesof light energy comprise visible light energy comprising a wavelengthwithin a range from about 400 nm to about 750 nm.

Clause 124. The method of clause 122, wherein each of the plurality offlashes of light energy comprises maximum distance across of no morethan about 1 mm.

Clause 125. The method of clause 122, wherein the plurality of flashesis generated within a time interval of no more than about 250 μs andoptionally no more than about 25 μs.

Clause 126. The method of clause 122, wherein the plurality of flashesis generated with an electrode movement distance of no more than about100 μm and optionally no more than about 10 μm.

Clause 127. The method of clause 122, wherein the plurality of flashesof light is distributed at a plurality of non-overlapping regions.

Clause 128. The method of clause 127, wherein the plurality ofnon-overlapping regions is located along the elongate electrode.

Clause 129. The method of clause 122, wherein the plurality of flashesof light are generated at a first rate with a first velocity of theelectrode and a second rate with a second velocity of the electrode,wherein the first rate is greater than the second rate when the firstvelocity is less than the second velocity and wherein the first rate isless than the second rate when the first velocity is greater than thesecond velocity.

Clause 130. The method of clause 129, wherein the plurality of flashesof light is generated at a substantially constant rate to within about25% and wherein one or more of a pulse rate or a burst rate of awaveform to the elongate electrode is varied in response to the avarying velocity of the electrode to maintain the substantially constantrate.

Clause 131. The method of clause 106, wherein the elongate electrodecomprises a filament and wherein the filament comprises one or more of awire or a thread.

Clause 132. The method of clause 106, wherein the elongate electrodecomprises a wire.

Clause 133. The method of clause 132, wherein a diameter of the wire iswithin a range from 5 μm to 200 μm, optionally from about 5 μm to about100 μm, optionally from about 5 μm to about 50 μm, optionally from about5 μm to about 25 μm, or optionally from about 5 μm to about 20 μm.

Clause 134. The method of clause 106, wherein the elongate electrodecomprises a cross-sectional distance and wherein the cross-sectionaldistance comprises no more than about 25 μm.

Clause 135. The method of clause 106, wherein the elongate electrodeoperatively coupled to the tensioning element comprises a mechanicalresonance frequency within a range from about 1kHz to about 100 kHz andoptionally within a range from about 2 kHz to about 50 kHz.

Clause 136. The method of clause 106, wherein the tensioning elementtensions the elongate electrode with a force within a range from about20 mN to about 2N and optionally within a range from about 50 mN toabout 1N and further optionally within a range from about 100 mN toabout 500 mN.

Clause 137. The method of clause 106, wherein the elongate electrodecomprises a mass per unit length within a range from about 0.2 μg·mm-1to about 3 μg·mm-1.

Clause 138. The method of clause 106, wherein elongate electrodecomprises a material selected from the group consisting of tungsten,nitinol, steel, copper, brass, titanium, stainless steel,beryllium-copper alloy, cupronickel alloy, palladium, platinum,platinum-iridium, silver, and aluminum.

Clause 139. The method of clause 106, wherein elongate electrodecomprises an axis along an elongate direction of the electrode andwherein the electrode incises tissue with movement in a directiontransverse to the axis.

Clause 140. The method of clause 106, wherein elongate electrode incisestissue in a direction transverse to an elongate direction of theelectrode at a velocity greater than about 1 m·s-1.

Clause 141. The method of clause 106, wherein elongate electrode incisestissue in a direction transverse to an elongate direction of theelectrode at a velocity within a range from about 0.5 cm·s-1 to about 10m·s-1 and optionally within a range from about 1 cm·s-1 to about 5m·s-1.

Clause 142. The method of clause 106, wherein the electrode incises anarea of tissue at a rate within a range from about 5 mm2·s-1 to about50,000 mm2·s-1 and optionally within a range from about 500 mm2·s-1 toabout 25,000 mm2·s-1.

Clause 143. The method of clause 106, wherein the electrical energysource delivers a waveform, wherein the waveform comprises one or moreof a pulsatile waveform, a sinusoidal waveform, a square waveform, asawtooth waveform, a triangular waveform, a fixed frequency waveform, avariable frequency waveform, or a gated waveform.

Clause 144. The method of clause 143, wherein the waveform comprises thesinusoidal waveform and wherein the sinusoidal waveform comprises afrequency within a range from about 0.5 MHz to about 2 MHz.

Clause 145. The method of clause 143, wherein the waveform comprises acombination of the sinusoidal waveform and the gated waveform andwherein the sinusoidal waveform comprises a frequency within a rangefrom about 0.5 MHz to about 2 MHz and wherein the gated waveformcomprises a gate frequency within a range from about 20 kHz to about 80kHz and a duty cycle within a range from about 35% to about 100%.

Clause 146. The method of clause 106, wherein a controller isoperatively coupled to the electrical energy source.

Clause 147. The method of clause 146, wherein the controller controlsparameters of the electrical energy source by modulating the waveformusing a parameter selected from the group consisting of a voltage, acurrent, a carrier frequency, a modulation frequency, a duty cycle, apower setpoint, a power limit, an energy per pulse setpoint, an energyper pulse limit, and a modulation envelope.

Clause 148. The method of clause 147, wherein the waveform comprises apulsatile voltage waveform comprising pulses and a substantiallyconstant frequency within a range from about 10 kHz to about 10 MHz andoptionally within a range from about 0.5 MHz to about 2 MHz.

Clause 149. The method of clause 148, wherein the waveform provides anenergy per pulse of within a range from about 0.5 μJ to about 50 μJ andoptionally within a range from about 1 μJ to about 10 μJ.

Clause 150. The method of clause 149, wherein the controller modulatesthe substantially constant frequency waveform to produce bursts.

Clause 151. The method of clause 150, wherein a frequency of the burstsis within a range from about 100 Hz and about 3 MHz and optionallywithin a range from about 1 kHz to about 100 kHz.

Clause 152. The method of clause 151, wherein the waveform from theelectrical energy source supplies an average power within a range fromabout 1 W to about 25 W.

Clause 153. The method of clause 110, wherein a translation elementoperatively coupled to the support structure directs the supportstructure along an axis of motion transverse to an elongate axis of theelectrode.

Clause 154. The method of clause 153, wherein the translation element isselected from the group consisting of a translation stage, a linearstage, a rotary stage, a rail, a rod, a cylindrical sleeve, a screw, aroller screw, a travelling nut, a rack, a pinion, a belt, a chain, alinear motion bearing, a rotary motion bearing, a cam, a flexure, and adovetail.

Clause 155. The method of clause 154, wherein an actuator operativelycoupled to the translation element moves the support structure along anaxis of motion.

Clause 156. The method of clause 155, wherein the translation element ismanually actuated.

Clause 157. The method of clause 155, wherein the actuator is selectedfrom the group consisting of a motor, a rotary motor, a squiggle motor,a linear motor, a solenoid, a rotary solenoid, a linear solenoid, avoice coil, a spring, a moving coil, a piezoelectric actuator, apneumatic actuator, a hydraulic actuator, and a fluidic actuator.

Clause 158. The method of clause 110, wherein a portion of the supportstructure comprises a material selected from the group consisting oftungsten, nitinol, steel, copper, brass, titanium, stainless steel,beryllium-copper alloy, cupronickel alloy, palladium, platinum,platinum-iridium, silver, aluminum, polyimide, PTFE, polyethylene,polypropylene, polycarbonate, poly(methyl methacrylate), acrylonitrilebutadiene styrene, polyamide, polylactide, polyoxymethylene, polyetherether ketone, polyvinyl chloride, polylactic acid, glass, and ceramic.

Clause 159. The method of clause 153, wherein the translation elementcomprises a first translation element having a first axis of motion anda second translation element having a second axis of motion differentfrom the first axis of motion.

Clause 160. The method of clause 159, wherein the first and secondtranslation elements are each selected from the group consisting of atranslation stage, a linear stage, a rotary stage, a rail, a rod, acylindrical sleeve, a screw, a roller screw, a travelling nut, a rack, apinion, a belt, a chain, a linear motion bearing, a rotary motionbearing, a cam, a flexure, and a dovetail.

Clause 161. The method of clause 160, wherein a contact plateoperatively coupled to the second translation element engages a portionof the tissue to shape the tissue prior to incising the tissue with theelectrode.

Clause 162. The method of clause 106, wherein a contact plateoperatively coupled to the elongate electrode engages a portion of acornea to shape the cornea prior to incising the cornea with theelectrode.

Clause 163. The method of clause 162, wherein the contact plate comprisea first contact plate have a first surface profile and a second contactplate having a second surface profile, a difference between the firstsurface profile and the second surface profile corresponding to arefractive correction of an eye to correct the refractive error of theeye.

Clause 164. The method of clause 162, wherein the contact platecomprises a free-form optical surface shaped to correct wavefrontaberrations an eye.

Clause 165. The method of clause 162, wherein the contact platecomprises a plurality of independently adjustable actuators to shape thecornea.

Clause 166. The method of clause 165, wherein the contact platecomprises a plurality of plates operatively coupled to the independentlyadjustable actuators to shape the cornea.

Clause 167. The method of clause 166, wherein each of the plurality ofplates is driven to a first position and a second position at each of aplurality of locations, a difference between the first position and thesecond position corresponding to a shape profile of tissue to beresected from the cornea to ameliorate refractive error of the eye.

Clause 168. The method of clause 167, wherein the plurality of locationscomprises a plurality of two-dimensional locations and the shape profilecomprises a three-dimensional tissue resection profile.

Clause 169. The method of clause 165, wherein the plurality of actuatorscomprises at least 10 actuators and optionally wherein the plurality ofactuators comprises at least 16 actuators and optionally wherein theplurality of actuators comprises at least 42 actuators and optionallywherein the plurality of actuators comprises at least 100 actuators.

Clause 170. The method of clause 165, wherein the contact platecomprises a deformable membrane operatively coupled to the plurality ofindependently adjustable actuators.

Clause 171. The method of clause 165, wherein the contact platecomprises a first configuration for a first incision with the electrodealong a first incision profile and a second configuration for a secondincision with the electrode along a second incision profile and whereina difference between the first incision profile and the second incisionprofile corresponds to a shape of a lenticule of tissue removed from thecornea to treat a refractive error of the eye.

Clause 172. The method of clause 162, wherein the contact plate isconfigured to correct one or more of sphere, cylinder, coma, sphericalaberration, or trefoil of an eye.

Clause 173. The method of clause 162, wherein a suction element engagestissue retain the tissue in contact with the second translation elementin a substantially fixed position while the first translation elementmoves the electrode to incise the tissue.

Clause 174. The method of clause 162, wherein sterile barrier is placedon the contact plate to maintain sterility of the eye.

Clause 175. The method of clause 174, wherein the sterile barriercomprises a thin conformal barrier to conform to the shape of thecontact plate with the sterile barrier between the eye and the contactplate.

Clause 176. The method of clause 174, wherein the sterile barriercomprises a peel-and-stick sterile barrier.

Clause 177. The method of clause 162, wherein: a length of the elongateelectrode is within a range from about 6 mm to about 12 mm; the tissuecomprises corneal tissue; the electrode comprises a wire having adiameter within a range from about 5 μm to about 20 μm; and wherein thetensioning element provides a tension to the electrode within a rangefrom about 100 mN to about 500 mN.

Clause 178. A method to treat a refractive error of an eye, the methodcomprising: incising corneal tissue with an elongate electrode byproviding electrical energy to the electrode; engaging a portion of acornea to shape the cornea with a contact plate prior to incising thecornea with the electrode; and wherein a support structure moves theelectrode relative to the plate and incises the corneal tissue with theelectrode.

Clause 179. The method of clause 178, wherein a translation elementoperatively coupled to the support structure and the elongate electrodetranslates the electrode to incise the corneal tissue.

Clause 180. The method of clause 178, wherein the contact plate comprisea first contact plate have a first surface profile and a second contactplate having a second surface profile, a difference between the firstsurface profile and the second surface profile corresponding to arefractive correction of an eye to correct the refractive error of theeye.

Clause 181. The method of clause 178, wherein the contact platecomprises a free-form optical surface shaped to correct wavefrontaberrations an eye.

Clause 182. The method of clause 178, wherein the contact platecomprises a plurality of independently adjustable actuators to shape thecornea.

Clause 183. The method of clause 182, wherein the contact platecomprises a plurality of plates operatively coupled to the independentlyadjustable actuators to shape the cornea.

Clause 184. The method of clause 183, wherein each of the plurality ofplates is configured to be driven to a first position and a secondposition at each of a plurality of locations, a difference between thefirst position and the second position corresponding to a shape profileof tissue to be resected from the cornea to ameliorate refractive errorof the eye.

Clause 185. The method of clause 184, wherein the plurality of locationscomprises a plurality of two-dimensional locations and the shape profilecomprises a three-dimensional tissue resection profile.

Clause 186. The method of clause 182, wherein the plurality of actuatorscomprises at least 10 actuators and optionally wherein the plurality ofactuators comprises at least 16 actuators and optionally wherein theplurality of actuators comprises at least 42 actuators and optionallywherein the plurality of actuators comprises at least 100 actuators.

Clause 187. The method of clause 182, wherein the contact platecomprises a deformable membrane operatively coupled to the plurality ofindependently adjustable actuators.

Clause 188. The method of clause 182, wherein the contact platecomprises a first configuration for a first incision with the electrodealong a first incision profile and a second configuration for a secondincision with the electrode along a second incision profile and whereina difference between the first incision profile and the second incisionprofile corresponds to a shape of a lenticule of tissue to be removedfrom the cornea to treat a refractive error of the eye.

Clause 189. The method of clause 178, wherein the contact plate isconfigured to correct one or more of sphere, cylinder, coma, sphericalaberration, or trefoil of an eye.

Clause 190. The method of clause 178, wherein a suction element engagesthe corneal tissue retain the corneal tissue in contact with the secondtranslation element in a substantially fixed position while the firsttranslation element moves the electrode to incise the tissue.

Clause 191. The method of clause 178, wherein a sterile barrier isplaced on the contact plate to maintain sterility of the eye.

Clause 192. The method of clause 191, wherein the sterile barriercomprises a thin conformal barrier to conform to the shape of thecontact plate with the sterile barrier between the eye and the contactplate.

Clause 193. The method of clause 191, wherein the sterile barriercomprises a peel-and-stick sterile barrier.

Clause 194. The method of clause 178, wherein: a length of the elongateelectrode is within a range from 6mm to 12mm; the electrode comprises awire having a diameter within a range from 5 μm to 20 μm; and whereinthe tensioning element provides a tension to the electrode within arange from 100 mN to 500 mN.

Clause 195. A method of treating a refractive error of an eye, themethod comprising: inserting an elongate electrode into a cornea of theeye; incising the cornea with the electrode to define a lenticle ofcorneal tissue within a pocket; and removing the lenticle; wherein thelenticle comprises a shape profile corresponding to treatment of therefractive error.

Clause 196. The method of clause 195, wherein the electrode is movedwith a first movement to define a first surface on a first side of thelenticle and moved with a second movement to define a second surface ona second side of the lenticle.

Clause 197. The method of clause 195, wherein the electrode is advanceddistally to define a first surface on a first side of the lenticle anddrawn proximally to define a second surface on a second side of thelenticle.

Clause 198. The method of clause 197, wherein a gap extends between theelongate electrode and the support structure and wherein the gap issized to receive tissue and wherein tissue extending into the gap isincised when the electrode is drawn proximally.

Clause 199. The method of clause 195, wherein a contact plate comprisesa first configuration to define a first surface on a first side of thelenticule and a second configuration to define a second surface on asecond side of the lenticule.

Clause 200. The method of clause 195, wherein a first contact platecomprises a first shape profile to define a first surface on a firstside of the lenticule and a second shape profile to define a secondsurface on a second side of the lenticule.

Clause 201. The method of clause 195, wherein the shape profilecomprises a thickness profile.

Clause 202. The system or method of any one of the preceding clauses,further comprising: a processor operatively coupled to the elongateelectrode to move the elongate electrode to incise tissue.

Embodiments of the present disclosure have been shown and described asset forth herein and are provided by way of example only. One ofordinary skill in the art will recognize numerous adaptations, changes,variations and substitutions without departing from the scope of thepresent disclosure. Several alternatives and combinations of theembodiments disclosed herein may be utilized without departing from thescope of the present disclosure and the inventions disclosed herein.Therefore, the scope of the presently disclosed inventions shall bedefined solely by the scope of the appended claims and the equivalentsthereof.

What is claimed is:
 1. A method for incising tissue with a plasma,comprising: incising tissue with an elongate electrode, the elongateelectrode configured to flex and generate the plasma to incise thetissue; wherein an electrical energy source is operatively coupled tothe elongate electrode and provides electrical energy to the electrodeto generate the plasma; and wherein a tensioning element is operativelycoupled to the elongate electrode and provides tension to the elongateelectrode to allow the elongate electrode to flex in response to theelongate electrode engaging the tissue and generating the plasma.
 2. Themethod of claim 1, wherein a plurality of arms is operatively coupled tothe electrode and the tensioning element.
 3. The method of claim 2,wherein the electrode is unsupported between the two arms.
 4. The methodof claim 2, wherein the electrode is configured to vibrate transverselyto an elongate axis of the electrode.
 5. The method of claim 2, whereina support structure is operatively coupled to the plurality of arms andthe tensioning element, wherein the support structure advances theplurality of arms, the tensioning element, and the elongate electrode toincise the tissue.
 6. The method of claim 5, wherein an incisionalportion of the elongate electrode is suspended between the plurality ofarms with tension from the tensioning element and wherein a gap extendsbetween the plurality of arms.
 7. The method of claim 6, wherein the gapextends between the incisional portion of the elongate electrode, theplurality of arms and the support structure.
 8. The method of claim 6,wherein the gap is sized to receive incised tissue along an incisionformed with the elongate electrode.
 9. The method of claim 5, whereinthe support structure is operatively coupled to one or more actuators tomove the elongate electrode in one or more directions.
 10. The method ofclaim 9, wherein the one or more actuators moves the electrode with avariable velocity.
 11. The method of claim 1, wherein the tensioningelement is selected from the group consisting of a spring, a coilspring, a leaf spring, a torsion spring, a mesh, a hinge, and a livinghinge.
 12. The method of claim 1, wherein the elongate electrodecomprises a first portion of an elongate filament and wherein thetensioning element comprises a second portion of the elongate filamentshaped to tension the elongate electrode.
 13. The method of claim 1,wherein an electrode assembly comprising a support structure isoperatively coupled to a plurality of arms and the tensioning element,wherein the electrode assembly advances the electrode into tissue toincise the tissue.
 14. The method of claim 1, wherein the electrodesequentially contacts a plurality of locations of the tissue to generatethe incision.
 15. The method of claim 14, wherein the plurality oflocations comprises a plurality of discontiguous locations.
 16. Themethod of claim 15, wherein the electrode vaporizes tissue in contactwith the electrode at each of the plurality of discontiguous locations.17. The method of claim 1, wherein the electrode generates a pluralityof flashes of light energy at a plurality of locations while theelectrode incises the tissue.
 18. The method of claim 17, wherein theplurality of flashes of light energy comprise visible light energycomprising a wavelength within a range from about 400 nm to about 750nm.
 19. The method of claim 17, wherein each of the plurality of flashesof light energy comprises maximum distance across of no more than about1 mm.
 20. The method of claim 17, wherein the plurality of flashes isgenerated within a time interval of no more than about 250 μs is andoptionally no more than about 25 μs.
 21. The method of claim 17, whereinthe plurality of flashes is generated with an electrode movementdistance of no more than about 100 μm and optionally no more than about10 μm.
 22. The method of claim 1, wherein a contact plate operativelycoupled to the elongate electrode engages a portion of a cornea to shapethe cornea prior to incising the cornea with the electrode.